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4e3dca0b81fbe7c9756eff61ffb86759e17623ac
littlefs/lfs.c
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Christopher Haster 4e3dca0b81 Partial implementation of a rudimentary mtree 
This became surprisingly tricky.

The main issue is knowing when to split mdirs, and how to determine
this without wasting erase cycles.

Unlike splitting btree nodes, we can't salvage failed compacts here. As
soon as the salvage commit is written to disk, the commit becomes immediately
visibile to the filesystem because it still exists in the mtree. This is
a problem if we lose power.

We're likely going to need to implement rbyd estimates. This is
something I hoped to avoid because it brings in quite a bit of
complexity and might lead to an annoying amount of storage waste since
our estimates will need to be conservative to avoid unrecoverable
situations.

---

Also changed the on-disk btree/branch struct to store a copy of the weight.

This was already required for the root of the btree, requiring the
weight to be stored in every btree pointer allows better code
deduplication at the cost of some redundancy on btree branches, where
the weight is already implied by the rbyd structure.

This weight is usually a single byte for most branches anyways.

This may be worth revisiting at some point to see if there's any other
unexpected tradeoffs.
2023-05-30 13:28:35 -05:00

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/*
* The little filesystem
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "lfs.h"
#include "lfs_util.h"
// some constants used throughout the code
#define LFS_BLOCK_NULL ((lfs_block_t)-1)
#define LFS_BLOCK_INLINE ((lfs_block_t)-2)
enum {
LFS_OK_RELOCATED = 1,
LFS_OK_DROPPED = 2,
LFS_OK_ORPHANED = 3,
};
enum {
LFS_CMP_EQ = 0,
LFS_CMP_LT = 1,
LFS_CMP_GT = 2,
};
/// Caching block device operations ///
static inline void lfs_cache_drop(lfs_t *lfs, lfs_cache_t *rcache) {
// do not zero, cheaper if cache is readonly or only going to be
// written with identical data (during relocates)
(void)lfs;
rcache->block = LFS_BLOCK_NULL;
}
static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
// zero to avoid information leak
memset(pcache->buffer, 0xff, lfs->cfg->cache_size);
pcache->block = LFS_BLOCK_NULL;
}
static int lfs_bd_read(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
if (block >= lfs->cfg->block_count ||
off+size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT;
}
while (size > 0) {
lfs_size_t diff = size;
if (pcache && block == pcache->block &&
off < pcache->off + pcache->size) {
if (off >= pcache->off) {
// is already in pcache?
diff = lfs_min(diff, pcache->size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// pcache takes priority
diff = lfs_min(diff, pcache->off-off);
}
if (block == rcache->block &&
off < rcache->off + rcache->size) {
if (off >= rcache->off) {
// is already in rcache?
diff = lfs_min(diff, rcache->size - (off-rcache->off));
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// rcache takes priority
diff = lfs_min(diff, rcache->off-off);
}
if (size >= hint && off % lfs->cfg->read_size == 0 &&
size >= lfs->cfg->read_size) {
// bypass cache?
diff = lfs_aligndown(diff, lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
// TODO this was a quick hack, the entire cache system probably
// requires a deeper look
//
// fix overlaps with our pcache
if (pcache
&& block == pcache->block
&& off < pcache->off + pcache->size
&& off + diff > pcache->off) {
lfs_off_t off_ = lfs_max(off, pcache->off);
lfs_size_t diff_ = lfs_min(
diff - (off_-off),
pcache->size - (off_-pcache->off));
memcpy(&data[off_-off],
&pcache->buffer[off_-pcache->off],
diff_);
}
data += diff;
off += diff;
size -= diff;
continue;
}
// load to cache, first condition can no longer fail
LFS_ASSERT(block < lfs->cfg->block_count);
rcache->block = block;
rcache->off = lfs_aligndown(off, lfs->cfg->read_size);
rcache->size = lfs_min(
lfs_min(
lfs_alignup(off+lfs_max(size, hint), lfs->cfg->read_size),
lfs->cfg->block_size)
- rcache->off,
lfs->cfg->cache_size);
int err = lfs->cfg->read(lfs->cfg, rcache->block,
rcache->off, rcache->buffer, rcache->size);
LFS_ASSERT(err <= 0);
if (err) {
return err;
}
// TODO this was a quick hack, the entire cache system probably
// requires a deeper look
//
// fix overlaps with our pcache
if (pcache
&& rcache->block == pcache->block
&& rcache->off < pcache->off + pcache->size
&& rcache->off + rcache->size > pcache->off) {
lfs_off_t off_ = lfs_max(rcache->off, pcache->off);
lfs_size_t size_ = lfs_min(
rcache->size - (off_-rcache->off),
pcache->size - (off_-pcache->off));
memcpy(&rcache->buffer[off_-rcache->off],
&pcache->buffer[off_-pcache->off],
size_);
}
}
return 0;
}
static int lfs_bd_cmp(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
lfs_size_t diff = 0;
// make sure our hint is at least as big as our buffer
hint = lfs_max(hint, size);
for (lfs_off_t i = 0; i < size; i += diff) {
uint8_t dat[8];
diff = lfs_min(size-i, sizeof(dat));
int err = lfs_bd_read(lfs,
pcache, rcache, hint-i,
block, off+i, &dat, diff);
if (err) {
return err;
}
int res = memcmp(dat, data + i, diff);
if (res) {
return res < 0 ? LFS_CMP_LT : LFS_CMP_GT;
}
}
return LFS_CMP_EQ;
}
static int lfs_bd_crc(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off, lfs_size_t size, uint32_t *crc) {
lfs_size_t diff = 0;
for (lfs_off_t i = 0; i < size; i += diff) {
uint8_t dat[8];
diff = lfs_min(size-i, sizeof(dat));
int err = lfs_bd_read(lfs,
pcache, rcache, hint-i,
block, off+i, &dat, diff);
if (err) {
return err;
}
*crc = lfs_crc(*crc, &dat, diff);
}
return 0;
}
static int lfs_bd_crc32c(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off, lfs_size_t size, uint32_t *crc) {
lfs_size_t diff = 0;
for (lfs_off_t i = 0; i < size; i += diff) {
uint8_t dat[8];
diff = lfs_min(size-i, sizeof(dat));
int err = lfs_bd_read(lfs,
pcache, rcache, lfs_max32(hint, size)-i,
block, off+i, &dat, diff);
if (err) {
return err;
}
*crc = lfs_crc32c(*crc, &dat, diff);
}
return 0;
}
#ifndef LFS_READONLY
static int lfs_bd_flush(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
if (pcache->block != LFS_BLOCK_NULL && pcache->block != LFS_BLOCK_INLINE) {
LFS_ASSERT(pcache->block < lfs->cfg->block_count);
lfs_size_t diff = lfs_alignup(pcache->size, lfs->cfg->prog_size);
int err = lfs->cfg->prog(lfs->cfg, pcache->block,
pcache->off, pcache->buffer, diff);
LFS_ASSERT(err <= 0);
if (err) {
return err;
}
if (validate) {
// check data on disk
lfs_cache_drop(lfs, rcache);
int res = lfs_bd_cmp(lfs,
NULL, rcache, diff,
pcache->block, pcache->off, pcache->buffer, diff);
if (res < 0) {
return res;
}
if (res != LFS_CMP_EQ) {
return LFS_ERR_CORRUPT;
}
}
lfs_cache_zero(lfs, pcache);
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_bd_sync(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
lfs_cache_drop(lfs, rcache);
int err = lfs_bd_flush(lfs, pcache, rcache, validate);
if (err) {
return err;
}
err = lfs->cfg->sync(lfs->cfg);
LFS_ASSERT(err <= 0);
return err;
}
#endif
#ifndef LFS_READONLY
static int lfs_bd_prog(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate,
lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
LFS_ASSERT(block == LFS_BLOCK_INLINE || block < lfs->cfg->block_count);
LFS_ASSERT(off + size <= lfs->cfg->block_size);
// update rcache if we overlap
if (rcache
&& block == rcache->block
&& off < rcache->off + rcache->size
&& off + size > rcache->off) {
lfs_off_t off_ = lfs_max(off, rcache->off);
lfs_size_t size_ = lfs_min(
size - (off_-off),
rcache->size - (off_-rcache->off));
memcpy(&rcache->buffer[off_-rcache->off], &data[off_-off], size_);
}
while (size > 0) {
if (block == pcache->block &&
off >= pcache->off &&
off < pcache->off + lfs->cfg->cache_size) {
// already fits in pcache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->cache_size - (off-pcache->off));
memcpy(&pcache->buffer[off-pcache->off], data, diff);
data += diff;
off += diff;
size -= diff;
pcache->size = lfs_max(pcache->size, off - pcache->off);
if (pcache->size == lfs->cfg->cache_size) {
// eagerly flush out pcache if we fill up
int err = lfs_bd_flush(lfs, pcache, rcache, validate);
if (err) {
return err;
}
}
continue;
}
// pcache must have been flushed, either by programming and
// entire block or manually flushing the pcache
LFS_ASSERT(pcache->block == LFS_BLOCK_NULL);
// prepare pcache, first condition can no longer fail
pcache->block = block;
pcache->off = lfs_aligndown(off, lfs->cfg->prog_size);
pcache->size = 0;
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_bd_erase(lfs_t *lfs, lfs_block_t block) {
LFS_ASSERT(block < lfs->cfg->block_count);
// make sure any caches are outdated appropriately here
LFS_ASSERT(lfs->pcache.block != block);
if (lfs->rcache.block == block) {
lfs_cache_drop(lfs, &lfs->rcache);
}
int err = lfs->cfg->erase(lfs->cfg, block);
LFS_ASSERT(err <= 0);
return err;
}
#endif
// TODO should these be the only bd APIs?
// simpler APIs if assume file caches are irrelevant
//
// note hint has two convenience:
// 1. 0 = minimal caching
// 2. block_size = maximal caching
//
static int lfsr_bd_read(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_size_t hint,
void *buffer, lfs_size_t size) {
// check for in-bounds
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
return lfs_bd_read(lfs, &lfs->pcache, &lfs->rcache, hint,
block, off, buffer, size);
}
// TODO merge lfsr_bd_readcsum/lfsr_bd_csum somehow?
static int lfsr_bd_readcsum(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_size_t hint,
void *buffer, lfs_size_t size,
uint32_t *csum_) {
int err = lfsr_bd_read(lfs, block, off, hint, buffer, size);
if (err) {
return err;
}
*csum_ = lfs_crc32c(*csum_, buffer, size);
return 0;
}
static int lfsr_bd_csum(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_size_t hint, lfs_size_t size,
uint32_t *crc_) {
// check for in-bounds
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
return lfs_bd_crc32c(lfs, &lfs->pcache, &lfs->rcache, hint,
block, off, size, crc_);
}
static int lfsr_bd_cmp(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_size_t hint,
const void *buffer, lfs_size_t size,
int *cmp) {
// check for in-bounds
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_RANGE;
}
int res = lfs_bd_cmp(lfs, &lfs->pcache, &lfs->rcache, hint,
block, off, buffer, size);
if (res < 0) {
return res;
}
// TODO this should be eventually flattened away
if (res == LFS_CMP_EQ) {
*cmp = 0;
} else if (res == LFS_CMP_LT) {
*cmp = -1;
} else {
*cmp = +1;
}
return 0;
}
// program data with optional checksum
static int lfsr_bd_prog(lfs_t *lfs, lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size,
uint32_t *csum_) {
// check for in-bounds
if (off+size > lfs->cfg->block_size) {
lfs_cache_zero(lfs, &lfs->pcache);
return LFS_ERR_RANGE;
}
int err = lfs_bd_prog(lfs, &lfs->pcache, &lfs->rcache, false,
block, off, buffer, size);
if (err) {
return err;
}
// optional checksum
if (csum_) {
*csum_ = lfs_crc32c(*csum_, buffer, size);
}
return 0;
}
static int lfsr_bd_sync(lfs_t *lfs) {
return lfs_bd_sync(lfs, &lfs->pcache, &lfs->rcache, false);
}
// TODO do we need this? should everything be checked by crc and validation
// be an optional ifdef?
static int lfsr_bd_progvalidate(lfs_t *lfs, lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size,
uint32_t *csum_) {
// check for in-bounds
if (off+size > lfs->cfg->block_size) {
lfs_cache_zero(lfs, &lfs->pcache);
return LFS_ERR_RANGE;
}
int err = lfs_bd_prog(lfs, &lfs->pcache, &lfs->rcache, true,
block, off, buffer, size);
if (err) {
return err;
}
if (csum_) {
*csum_ = lfs_crc32c(*csum_, buffer, size);
}
return 0;
}
static int lfsr_bd_syncvalidate(lfs_t *lfs) {
return lfs_bd_sync(lfs, &lfs->pcache, &lfs->rcache, true);
}
static int lfsr_bd_erase(lfs_t *lfs, lfs_block_t block) {
return lfs_bd_erase(lfs, block);
}
/// Small type-level utilities ///
// operations on block pairs
static inline void lfs_pair_swap(lfs_block_t pair[2]) {
lfs_block_t t = pair[0];
pair[0] = pair[1];
pair[1] = t;
}
static inline bool lfs_pair_isnull(const lfs_block_t pair[2]) {
return pair[0] == LFS_BLOCK_NULL || pair[1] == LFS_BLOCK_NULL;
}
static inline int lfs_pair_cmp(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return !(paira[0] == pairb[0] || paira[1] == pairb[1] ||
paira[0] == pairb[1] || paira[1] == pairb[0]);
}
static inline bool lfs_pair_issync(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return (paira[0] == pairb[0] && paira[1] == pairb[1]) ||
(paira[0] == pairb[1] && paira[1] == pairb[0]);
}
static inline void lfs_pair_fromle32(lfs_block_t pair[2]) {
pair[0] = lfs_fromle32(pair[0]);
pair[1] = lfs_fromle32(pair[1]);
}
#ifndef LFS_READONLY
static inline void lfs_pair_tole32(lfs_block_t pair[2]) {
pair[0] = lfs_tole32(pair[0]);
pair[1] = lfs_tole32(pair[1]);
}
#endif
// operations on 32-bit entry tags
typedef uint32_t lfs_tag_t;
typedef int32_t lfs_stag_t;
#define LFS_MKTAG(type, id, size) \
(((lfs_tag_t)(type) << 20) | ((lfs_tag_t)(id) << 10) | (lfs_tag_t)(size))
#define LFS_MKTAG_IF(cond, type, id, size) \
((cond) ? LFS_MKTAG(type, id, size) : LFS_MKTAG(LFS_FROM_NOOP, 0, 0))
#define LFS_MKTAG_IF_ELSE(cond, type1, id1, size1, type2, id2, size2) \
((cond) ? LFS_MKTAG(type1, id1, size1) : LFS_MKTAG(type2, id2, size2))
static inline bool lfs_tag_isvalid(lfs_tag_t tag) {
return !(tag & 0x80000000);
}
static inline bool lfs_tag_isdelete(lfs_tag_t tag) {
return ((int32_t)(tag << 22) >> 22) == -1;
}
static inline uint16_t lfs_tag_type1(lfs_tag_t tag) {
return (tag & 0x70000000) >> 20;
}
static inline uint16_t lfs_tag_type2(lfs_tag_t tag) {
return (tag & 0x78000000) >> 20;
}
static inline uint16_t lfs_tag_type3(lfs_tag_t tag) {
return (tag & 0x7ff00000) >> 20;
}
static inline uint8_t lfs_tag_chunk(lfs_tag_t tag) {
return (tag & 0x0ff00000) >> 20;
}
static inline int8_t lfs_tag_splice(lfs_tag_t tag) {
return (int8_t)lfs_tag_chunk(tag);
}
static inline uint16_t lfs_tag_id(lfs_tag_t tag) {
return (tag & 0x000ffc00) >> 10;
}
static inline lfs_size_t lfs_tag_size(lfs_tag_t tag) {
return tag & 0x000003ff;
}
static inline lfs_size_t lfs_tag_dsize(lfs_tag_t tag) {
return sizeof(tag) + lfs_tag_size(tag + lfs_tag_isdelete(tag));
}
// 16-bit metadata tags
enum lfsr_tag_type {
LFSR_TAG_UNR = 0x0002,
LFSR_TAG_MKUNR = 0x0006, // in-device only
LFSR_TAG_SUPERMAGIC = 0x0030,
LFSR_TAG_SUPERCONFIG = 0x0040,
LFSR_TAG_SUPERMDIR = 0x0110,
LFSR_TAG_NAME = 0x1000,
LFSR_TAG_BNAME = 0x1000,
LFSR_TAG_MKBNAME = 0x1004, // in-device only
LFSR_TAG_REG = 0x1010,
LFSR_TAG_MKREG = 0x1014, // in-device only
LFSR_TAG_DIR = 0x1020,
LFSR_TAG_MKDIR = 0x1024, // in-device only
LFSR_TAG_STRUCT = 0x3000,
LFSR_TAG_INLINED = 0x3000,
LFSR_TAG_BLOCK = 0x3100,
LFSR_TAG_BRANCH = 0x3200,
LFSR_TAG_MKBRANCH = 0x3204, // in-device only
LFSR_TAG_RMBRANCH = 0x3202,
// TODO do we actually need BTREE?
// LFSR_TAG_BTREE = 0x3300,
LFSR_TAG_MDIR = 0x3400,
LFSR_TAG_RMMDIR = 0x3402,
LFSR_TAG_UATTR = 0x4000,
LFSR_TAG_MKUATTR = 0x4004, // in-device only
LFSR_TAG_RMUATTR = 0x4002,
LFSR_TAG_ALT = 0x0008,
LFSR_TAG_ALTBLE = 0x0008,
LFSR_TAG_ALTRLE = 0x000a,
LFSR_TAG_ALTBGT = 0x000c,
LFSR_TAG_ALTRGT = 0x000e,
LFSR_TAG_CRC = 0x0004,
LFSR_TAG_FCRC = 0x1004,
// in-device only
LFSR_TAG_GROW = 0xf000,
LFSR_TAG_SHRINK = 0xf010,
LFSR_TAG_FROM = 0xf020,
};
#define LFSR_TAG_ALT_(color, dir, key) \
(LFSR_TAG_ALT \
| ((0x1 & (lfsr_tag_t)(color)) << 1) \
| ((0x1 & (lfsr_tag_t)(dir)) << 2) \
| ((0xfff0 & (lfsr_tag_t)(key))))
#define LFSR_TAG_ALT(color, dir, key) \
(LFSR_TAG_ALT##color##dir \
| ((0xfff0 & (lfsr_tag_t)(key))))
#define LFSR_TAG_UATTR(attr) \
(LFSR_TAG_UATTR \
| ((0xff & (lfsr_tag_t)(attr)) << 4))
#define LFSR_TAG_MKUATTR(attr) \
(LFSR_TAG_MKUATTR \
| ((0xff & (lfsr_tag_t)(attr)) << 4))
#define LFSR_TAG_RMUATTR(attr) \
(LFSR_TAG_RMUATTR \
| ((0xff & (lfsr_tag_t)(attr)) << 4))
// tag type operations
static inline lfsr_tag_t lfsr_tag_suptype(lfsr_tag_t tag) {
return tag & 0xf00f;
}
static inline uint8_t lfsr_tag_subtype(lfsr_tag_t tag) {
return (tag & 0x0ff0) >> 4;
}
static inline bool lfsr_tag_ismk(lfsr_tag_t tag) {
return tag & 0x4;
}
static inline lfsr_tag_t lfsr_tag_setmk(lfsr_tag_t tag) {
return tag | 0x4;
}
static inline lfsr_tag_t lfsr_tag_setnomk(lfsr_tag_t tag) {
return tag & ~0x4;
}
static inline bool lfsr_tag_isrm(lfsr_tag_t tag) {
return tag & 0x2;
}
static inline lfsr_tag_t lfsr_tag_setrm(lfsr_tag_t tag) {
return tag | 0x2;
}
static inline bool lfsr_tag_istrunk(lfsr_tag_t tag) {
return (tag & 0xc) != 0x4;
}
static inline bool lfsr_tag_isalt(lfsr_tag_t tag) {
return tag & 0x8;
}
static inline lfsr_tag_t lfsr_tag_next(lfsr_tag_t tag) {
return tag + 0x10;
}
// lfsr_rbyd_append specific flags
static inline bool lfsr_tag_isfound(lfsr_tag_t tag) {
return tag & 0x1;
}
static inline lfsr_tag_t lfsr_tag_setfound(lfsr_tag_t tag) {
return tag | 0x1;
}
static inline bool lfsr_tag_isupper(lfsr_tag_t tag) {
return tag & 0x4;
}
static inline bool lfsr_tag_islower(lfsr_tag_t tag) {
return !lfsr_tag_isupper(tag);
}
static inline lfsr_tag_t lfsr_tag_setupper(lfsr_tag_t tag) {
return tag | 0x4;
}
static inline bool lfsr_tag_hasdiverged(lfsr_tag_t tag) {
return tag & 0x8;
}
static inline lfsr_tag_t lfsr_tag_setdiverged(lfsr_tag_t tag) {
return tag | 0x8;
}
// alt operations
static inline bool lfsr_tag_isblack(lfsr_tag_t tag) {
return !(tag & 0x2);
}
static inline bool lfsr_tag_isred(lfsr_tag_t tag) {
return tag & 0x2;
}
static inline lfsr_tag_t lfsr_tag_setblack(lfsr_tag_t tag) {
return tag & ~0x2;
}
static inline lfsr_tag_t lfsr_tag_setred(lfsr_tag_t tag) {
return tag | 0x2;
}
static inline bool lfsr_tag_isle(lfsr_tag_t tag) {
return !(tag & 0x4);
}
static inline bool lfsr_tag_isgt(lfsr_tag_t tag) {
return tag & 0x4;
}
static inline lfsr_tag_t lfsr_tag_isparallel(lfsr_tag_t a, lfsr_tag_t b) {
return (a & 0x4) == (b & 0x4);
}
static inline lfsr_tag_t lfsr_tag_key(lfsr_tag_t tag) {
return tag & ~0xf;
}
static inline bool lfsr_tag_follow(lfsr_tag_t alt, lfs_size_t weight,
lfs_ssize_t lower, lfs_ssize_t upper,
lfs_ssize_t id, lfsr_tag_t tag) {
if (lfsr_tag_isgt(alt)) {
return id > upper - (lfs_ssize_t)weight - 1
|| (id == upper - (lfs_ssize_t)weight - 1
&& lfsr_tag_key(tag) > lfsr_tag_key(alt));
} else {
return id < lower + (lfs_ssize_t)weight
|| (id == lower + (lfs_ssize_t)weight
&& lfsr_tag_key(tag) <= lfsr_tag_key(alt));
}
}
static inline bool lfsr_tag_follow2(
lfsr_tag_t alt, lfs_size_t weight,
lfsr_tag_t alt2, lfs_size_t weight2,
lfs_ssize_t lower, lfs_ssize_t upper,
lfs_ssize_t id, lfsr_tag_t tag) {
if (lfsr_tag_isred(alt2) && lfsr_tag_isparallel(alt, alt2)) {
weight += weight2;
}
return lfsr_tag_follow(alt, weight, lower, upper, id, tag);
}
static inline bool lfsr_tag_prune2(
lfsr_tag_t alt, lfs_ssize_t weight,
lfsr_tag_t alt2, lfs_ssize_t weight2,
lfs_ssize_t lower_id, lfs_ssize_t upper_id,
lfsr_tag_t lower_tag, lfsr_tag_t upper_tag) {
if (lfsr_tag_isgt(alt)) {
return lfsr_tag_follow2(
alt, weight,
alt2, weight2,
lower_id, upper_id,
lower_id, lower_tag);
} else {
return lfsr_tag_follow2(
alt, weight,
alt2, weight2,
lower_id, upper_id,
upper_id-1, upper_tag-0x10);
}
}
static inline void lfsr_tag_flip(lfsr_tag_t *alt, lfs_size_t *weight,
lfs_ssize_t lower, lfs_ssize_t upper) {
*alt = *alt ^ 0x4;
*weight = (upper-lower) - *weight - 1;
}
static inline void lfsr_tag_flip2(lfsr_tag_t *alt, lfs_size_t *weight,
lfsr_tag_t alt2, lfs_size_t weight2,
lfs_ssize_t lower, lfs_ssize_t upper) {
if (lfsr_tag_isred(alt2)) {
*weight += weight2;
}
lfsr_tag_flip(alt, weight, lower, upper);
}
static inline void lfsr_tag_trim(
lfsr_tag_t alt, lfs_size_t weight,
lfs_ssize_t *lower_id, lfs_ssize_t *upper_id,
lfsr_tag_t *lower_tag, lfsr_tag_t *upper_tag) {
if (lfsr_tag_isgt(alt)) {
*upper_id -= weight;
if (upper_tag) {
*upper_tag = alt + 0x10;
}
} else {
*lower_id += weight;
if (lower_tag) {
*lower_tag = alt + 0x10;
}
}
}
static inline void lfsr_tag_trim2(
lfsr_tag_t alt, lfs_size_t weight,
lfsr_tag_t alt2, lfs_size_t weight2,
lfs_ssize_t *lower_id, lfs_ssize_t *upper_id,
lfsr_tag_t *lower_tag, lfsr_tag_t *upper_tag) {
if (lfsr_tag_isred(alt2)) {
lfsr_tag_trim(alt2, weight2, lower_id, upper_id, lower_tag, upper_tag);
}
lfsr_tag_trim(alt, weight, lower_id, upper_id, lower_tag, upper_tag);
}
// support for encoding/decoding tags on disk
// each piece of metadata in an rbyd tree is prefixed with a 3-piece tag:
//
// - 16-bit type => 2 byte le16
// - 32-bit id/weight => 5 byte leb128 (worst case)
// - 32-bit size/jump => 5 byte leb128 (worst case)
// => 12 bytes total
//
#define LFSR_TAG_DSIZE (2+5+5)
static lfs_ssize_t lfsr_bd_readtag(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_size_t hint,
lfsr_tag_t *tag_, lfs_size_t *weight_, lfs_size_t *size_,
uint32_t *csum_) {
// read the largest possible tag size
lfs_size_t tsize = lfs_min32(LFSR_TAG_DSIZE, lfs->cfg->block_size-off);
uint8_t buf[LFSR_TAG_DSIZE];
int err = lfsr_bd_read(lfs, block, off, hint, &buf, tsize);
if (err) {
return err;
}
if (tsize < 2) {
return LFS_ERR_CORRUPT;
}
uint16_t tag = lfs_fromle16_(&buf[0]);
ssize_t d = 2;
if (csum_) {
// on-disk, the tags valid bit must reflect the parity of the
// preceding data, fortunately for crc32c, this is the same as the
// parity of the crc
//
// note we need to do this before leb128 decoding as we may not have
// valid leb128 if we're erased, but we shouldn't treat a truncated
// leb128 here as corruption
if ((tag & 1) != (lfs_popc(*csum_) & 1)) {
return LFS_ERR_INVAL;
}
}
lfs_size_t weight;
lfs_ssize_t d_ = lfs_fromleb128(&weight, &buf[d], tsize-d);
if (d_ < 0) {
return d_;
}
d += d_;
if (weight > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
lfs_size_t size;
d_ = lfs_fromleb128(&size, &buf[d], tsize-d);
if (d_ < 0) {
return d_;
}
d += d_;
if (size > 0x7fffffff) {
return LFS_ERR_CORRUPT;
}
// optionally crc
if (csum_) {
*csum_ = lfs_crc32c(*csum_, buf, d);
}
// save what we found, note we make a few tweaks on-disk => in-device
// - clear the valid bit from tag, we checked this earlier
// - adjust id so reserved id is -1, so we don't have mixed zero/one indexed
//
*tag_ = tag & ~0x1;
*weight_ = weight;
*size_ = size;
return d;
}
static lfs_ssize_t lfsr_bd_progtag(lfs_t *lfs,
lfs_block_t block, lfs_off_t off,
lfsr_tag_t tag, lfs_size_t weight, lfs_size_t size,
uint32_t *csum_) {
// check for underflow issues
LFS_ASSERT(weight < 0x80000000);
LFS_ASSERT(size < 0x80000000);
// make sure to include the parity of the current crc
tag |= lfs_popc(*csum_) & 1;
// encode into an le16 and pair of leb128s
uint8_t buf[LFSR_TAG_DSIZE];
lfs_tole16_(tag, &buf[0]);
lfs_size_t d = 2;
ssize_t d_ = lfs_toleb128(weight, &buf[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfs_toleb128(size, &buf[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
int err = lfsr_bd_prog(lfs, block, off, &buf, d, csum_);
if (err) {
return err;
}
return d;
}
/// lfsr_data_t stuff ///
// either an on-disk or in-device data pointer
typedef union lfsr_data {
// sign(size)=0 => in-device
// sign(size)=1 => on-disk
lfs_size_t size;
struct {
lfs_size_t size;
const uint8_t *buffer;
} buf;
struct {
lfs_size_t size;
lfs_block_t block;
lfs_off_t off;
} disk;
} lfsr_data_t;
#define LFSR_DATA_NULL \
((lfsr_data_t){.size=0})
#define LFSR_DATA_BUF(_buffer, _size) \
((lfsr_data_t){.buf={ \
.size=_size, \
.buffer=(const void*)(_buffer)}})
#define LFSR_DATA_DISK(_block, _off, _size) \
((lfsr_data_t){.disk={ \
.size=(0x80000000 | (_size)), \
.block=_block, \
.off=_off}})
static inline bool lfsr_data_ondisk(lfsr_data_t data) {
return data.size & 0x80000000;
}
static inline lfs_size_t lfsr_data_size(lfsr_data_t data) {
return data.size & 0x7fffffff;
}
static inline lfs_size_t lfsr_data_setondisk(lfs_size_t size) {
return size | 0x80000000;
}
static lfsr_data_t lfsr_data_add(lfsr_data_t data, lfs_off_t off) {
// limit our off to data range
lfs_off_t off_ = lfs_min32(off, lfsr_data_size(data));
if (lfsr_data_ondisk(data)) {
data.disk.off += off_;
data.disk.size -= off_;
} else {
data.buf.buffer += off_;
data.buf.size -= off_;
}
return data;
}
// data<->bd interactions
static lfs_ssize_t lfsr_data_read(lfs_t *lfs, lfsr_data_t data,
lfs_off_t off, void *buffer, lfs_size_t size) {
// limit our off/size to data range
lfs_off_t off_ = lfs_min32(off, lfsr_data_size(data));
lfs_size_t hint_ = lfsr_data_size(data)-off_;
lfs_size_t size_ = lfs_min32(size, hint_);
if (lfsr_data_ondisk(data)) {
int err = lfsr_bd_read(lfs, data.disk.block, data.disk.off+off_,
// note our hint includes the full data range
hint_,
buffer, size_);
if (err) {
return err;
}
} else {
memcpy(buffer, data.buf.buffer+off_, size_);
}
return size_;
}
static lfs_ssize_t lfsr_data_readle32(lfs_t *lfs, lfsr_data_t data,
lfs_off_t off, uint32_t *word) {
lfs_ssize_t d = lfsr_data_read(lfs, data, off, word, sizeof(uint32_t));
if (d < 0) {
return d;
}
// truncated?
if ((lfs_size_t)d < sizeof(uint32_t)) {
return LFS_ERR_CORRUPT;
}
*word = lfs_fromle32_(word);
return sizeof(uint32_t);
}
static lfs_ssize_t lfsr_data_readleb128(lfs_t *lfs, lfsr_data_t data,
lfs_off_t off, uint32_t *word) {
// for 32-bits we can assume worst-case leb128 size is 5-bytes
uint8_t buf[5];
lfs_ssize_t d = lfsr_data_read(lfs, data, off, buf, 5);
if (d < 0) {
return d;
}
return lfs_fromleb128(word, buf, d);
}
static int lfsr_data_cmp(lfs_t *lfs, lfsr_data_t data,
lfs_off_t off, const void *buffer, lfs_size_t size,
int *cmp) {
// limit our off/size to data range
lfs_off_t off_ = lfs_min32(off, lfsr_data_size(data));
lfs_size_t hint_ = lfsr_data_size(data)-off_;
// return early if our size doesn't match
if (hint_ < size) {
*cmp = -1;
return 0;
} else if (hint_ > size) {
*cmp = +1;
return 0;
}
if (lfsr_data_ondisk(data)) {
int err = lfsr_bd_cmp(lfs, data.disk.block, data.disk.off+off_, 0,
buffer, size,
cmp);
if (err) {
return err;
}
} else {
*cmp = memcmp(data.buf.buffer+off_, buffer, size);
}
return 0;
}
static lfs_ssize_t lfsr_bd_progdata(lfs_t *lfs,
lfs_block_t block, lfs_off_t off,
lfsr_data_t data,
uint32_t *csum_) {
if (lfsr_data_ondisk(data)) {
// TODO byte-level copies have been a pain point, works for prototyping
// but can this be better? configurable? leverage
// rcache/pcache directly?
uint8_t dat;
for (lfs_size_t i = 0; i < lfsr_data_size(data); i++) {
int err = lfsr_bd_read(lfs, data.disk.block, data.disk.off+i,
lfsr_data_size(data)-i,
&dat, 1);
if (err) {
return err;
}
err = lfsr_bd_prog(lfs, block, off+i,
&dat, 1,
csum_);
if (err) {
return err;
}
}
} else {
int err = lfsr_bd_prog(lfs, block, off,
data.buf.buffer, lfsr_data_size(data),
csum_);
if (err) {
return err;
}
}
return 0;
}
// operations on attribute lists
struct lfs_mattr {
lfs_tag_t tag;
const void *buffer;
};
struct lfs_diskoff {
lfs_block_t block;
lfs_off_t off;
};
#define LFS_MKATTRS(...) \
(struct lfs_mattr[]){__VA_ARGS__}, \
sizeof((struct lfs_mattr[]){__VA_ARGS__}) / sizeof(struct lfs_mattr)
typedef struct lfsr_attr {
lfs_ssize_t id;
lfsr_tag_t tag;
lfs_ssize_t delta;
lfsr_data_t data;
} lfsr_attr_t;
#define LFSR_ATTR_DATA_(_id, _tag, _delta, _data) \
((const lfsr_attr_t){_id, _tag, _delta, _data})
#define LFSR_ATTR_DATA(_id, _type, _delta, _data) \
LFSR_ATTR_DATA_(_id, LFSR_TAG_##_type, _delta, _data)
#define LFSR_ATTR_(_id, _tag, _delta, _buffer, _size) \
LFSR_ATTR_DATA_(_id, _tag, _delta, LFSR_DATA_BUF(_buffer, _size))
#define LFSR_ATTR(_id, _type, _delta, _buffer, _size) \
LFSR_ATTR_(_id, LFSR_TAG_##_type, _delta, _buffer, _size)
#define LFSR_ATTR_DISK_(_id, _tag, _delta, _block, _off, _size) \
LFSR_ATTR_DATA_(_id, _tag, _delta, LFSR_DATA_DISK(_block, _off, _size))
#define LFSR_ATTR_DISK(_id, _type, _delta, _block, _off, _size) \
LFSR_ATTR_DISK_(_id, LFSR_TAG_##_type, _delta, _block, _off, _size)
#define LFSR_ATTR_NOOP LFSR_ATTR(-1, UNR, 0, NULL, 0)
#define LFSR_ATTRS(...) \
(const lfsr_attr_t[]){__VA_ARGS__}, \
sizeof((const lfsr_attr_t[]){__VA_ARGS__}) / sizeof(lfsr_attr_t)
//struct lfsr_attr_from {
// const lfsr_rbyd_t *rbyd;
// const struct lfsr_attr *attrs;
// lfs_size_t start;
//};
//
//#define LFSR_ATTR_FROM(_id, _rbyd, _attrs, _start, _stop, _next)
// LFSR_ATTR(FROM, _id,
// (&(const struct lfsr_attr_from){_rbyd, _attrs, _start}),
// (_stop)-(_start), _next)
//
//#define LFS_MKRATTR_(...)
// (&(const struct lfsr_attr){__VA_ARGS__})
//
//#define LFS_MKRATTR(type1, type2, id, buffer, size, next)
// (&(const struct lfsr_attr){
// LFS_MKRTAG(type1, type2, id),
// buffer, size, next})
//
//#define LFS_MKRRMATTR(type1, type2, id, next)
// (&(const struct lfsr_attr){
// LFS_MKRRMTAG(type1, type2, id),
// NULL, 0, next})
// find state when looking up by name
typedef struct lfsr_find {
// what to search for
const char *name;
lfs_size_t name_size;
// if found, the tag/id will be placed in found_tag/found_id,
// otherwise found_tag will be zero and found_id will be set to
// the largest, smaller id (a good place to insert)
lfs_ssize_t predicted_id;
lfs_ssize_t found_id;
lfsr_tag_t predicted_tag;
lfsr_tag_t found_tag;
} lfsr_find_t;
// operations on global state
static inline void lfs_gstate_xor(lfs_gstate_t *a, const lfs_gstate_t *b) {
for (int i = 0; i < 3; i++) {
((uint32_t*)a)[i] ^= ((const uint32_t*)b)[i];
}
}
static inline bool lfs_gstate_iszero(const lfs_gstate_t *a) {
for (int i = 0; i < 3; i++) {
if (((uint32_t*)a)[i] != 0) {
return false;
}
}
return true;
}
#ifndef LFS_READONLY
static inline bool lfs_gstate_hasorphans(const lfs_gstate_t *a) {
return lfs_tag_size(a->tag);
}
static inline uint8_t lfs_gstate_getorphans(const lfs_gstate_t *a) {
return lfs_tag_size(a->tag);
}
static inline bool lfs_gstate_hasmove(const lfs_gstate_t *a) {
return lfs_tag_type1(a->tag);
}
#endif
static inline bool lfs_gstate_hasmovehere(const lfs_gstate_t *a,
const lfs_block_t *pair) {
return lfs_tag_type1(a->tag) && lfs_pair_cmp(a->pair, pair) == 0;
}
static inline void lfs_gstate_fromle32(lfs_gstate_t *a) {
a->tag = lfs_fromle32(a->tag);
a->pair[0] = lfs_fromle32(a->pair[0]);
a->pair[1] = lfs_fromle32(a->pair[1]);
}
#ifndef LFS_READONLY
static inline void lfs_gstate_tole32(lfs_gstate_t *a) {
a->tag = lfs_tole32(a->tag);
a->pair[0] = lfs_tole32(a->pair[0]);
a->pair[1] = lfs_tole32(a->pair[1]);
}
#endif
// operations on forward-CRCs used to track erased state
struct lfs_fcrc {
lfs_size_t size;
uint32_t crc;
};
static void lfs_fcrc_fromle32(struct lfs_fcrc *fcrc) {
fcrc->size = lfs_fromle32(fcrc->size);
fcrc->crc = lfs_fromle32(fcrc->crc);
}
#ifndef LFS_READONLY
static void lfs_fcrc_tole32(struct lfs_fcrc *fcrc) {
fcrc->size = lfs_tole32(fcrc->size);
fcrc->crc = lfs_tole32(fcrc->crc);
}
#endif
// fcrc on-disk encoding
typedef struct lfsr_fcrc {
lfs_size_t size;
uint32_t crc;
} lfsr_fcrc_t;
// 1 leb128 + 1 crc32c => 9 bytes (worst case)
#define LFSR_FCRC_DSIZE (5+4)
static lfs_ssize_t lfsr_fcrc_todisk(lfs_t *lfs, const lfsr_fcrc_t *fcrc,
uint8_t buffer[static LFSR_FCRC_DSIZE]) {
(void)lfs;
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(fcrc->size, &buffer[0], 5);
if (d_ < 0) {
return d_;
}
d += d_;
lfs_tole32_(fcrc->crc, &buffer[d]);
d += 4;
return d;
}
static lfs_ssize_t lfsr_fcrc_fromdisk(lfs_t *lfs, lfsr_fcrc_t *fcrc,
lfsr_data_t data) {
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfsr_data_readleb128(lfs, data, d, &fcrc->size);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfsr_data_readle32(lfs, data, d, &fcrc->crc);
if (d_ < 0) {
return d_;
}
d += d_;
return d;
}
// other endianness operations
static void lfs_ctz_fromle32(struct lfs_ctz *ctz) {
ctz->head = lfs_fromle32(ctz->head);
ctz->size = lfs_fromle32(ctz->size);
}
#ifndef LFS_READONLY
static void lfs_ctz_tole32(struct lfs_ctz *ctz) {
ctz->head = lfs_tole32(ctz->head);
ctz->size = lfs_tole32(ctz->size);
}
#endif
static inline void lfs_superblock_fromle32(lfs_superblock_t *superblock) {
superblock->version = lfs_fromle32(superblock->version);
superblock->block_size = lfs_fromle32(superblock->block_size);
superblock->block_count = lfs_fromle32(superblock->block_count);
superblock->name_max = lfs_fromle32(superblock->name_max);
superblock->file_max = lfs_fromle32(superblock->file_max);
superblock->attr_max = lfs_fromle32(superblock->attr_max);
}
#ifndef LFS_READONLY
static inline void lfs_superblock_tole32(lfs_superblock_t *superblock) {
superblock->version = lfs_tole32(superblock->version);
superblock->block_size = lfs_tole32(superblock->block_size);
superblock->block_count = lfs_tole32(superblock->block_count);
superblock->name_max = lfs_tole32(superblock->name_max);
superblock->file_max = lfs_tole32(superblock->file_max);
superblock->attr_max = lfs_tole32(superblock->attr_max);
}
#endif
#ifndef LFS_NO_ASSERT
static bool lfs_mlist_isopen(struct lfs_mlist *head,
struct lfs_mlist *node) {
for (struct lfs_mlist **p = &head; *p; p = &(*p)->next) {
if (*p == (struct lfs_mlist*)node) {
return true;
}
}
return false;
}
#endif
static void lfs_mlist_remove(lfs_t *lfs, struct lfs_mlist *mlist) {
for (struct lfs_mlist **p = &lfs->mlist; *p; p = &(*p)->next) {
if (*p == mlist) {
*p = (*p)->next;
break;
}
}
}
static void lfs_mlist_append(lfs_t *lfs, struct lfs_mlist *mlist) {
mlist->next = lfs->mlist;
lfs->mlist = mlist;
}
/// Internal operations predeclared here ///
#ifndef LFS_READONLY
static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs, int attrcount);
static int lfs_dir_compact(lfs_t *lfs,
lfs_mdir_t *dir, const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *source, uint16_t begin, uint16_t end);
static lfs_ssize_t lfs_file_flushedwrite(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size);
static lfs_ssize_t lfs_file_rawwrite(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size);
static int lfs_file_rawsync(lfs_t *lfs, lfs_file_t *file);
static int lfs_file_outline(lfs_t *lfs, lfs_file_t *file);
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file);
static int lfs_fs_deorphan(lfs_t *lfs, bool powerloss);
static int lfs_fs_preporphans(lfs_t *lfs, int8_t orphans);
static void lfs_fs_prepmove(lfs_t *lfs,
uint16_t id, const lfs_block_t pair[2]);
static int lfs_fs_pred(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *pdir);
static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *parent);
static int lfs_fs_forceconsistency(lfs_t *lfs);
#endif
#ifdef LFS_MIGRATE
static int lfs1_traverse(lfs_t *lfs,
int (*cb)(void*, lfs_block_t), void *data);
#endif
static int lfs_dir_rawrewind(lfs_t *lfs, lfs_dir_t *dir);
static lfs_ssize_t lfs_file_flushedread(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size);
static lfs_ssize_t lfs_file_rawread(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size);
static int lfs_file_rawclose(lfs_t *lfs, lfs_file_t *file);
static lfs_soff_t lfs_file_rawsize(lfs_t *lfs, lfs_file_t *file);
static lfs_ssize_t lfs_fs_rawsize(lfs_t *lfs);
static int lfs_fs_rawtraverse(lfs_t *lfs,
int (*cb)(void *data, lfs_block_t block), void *data,
bool includeorphans);
static int lfs_deinit(lfs_t *lfs);
static int lfs_rawunmount(lfs_t *lfs);
/// Block allocator ///
#ifndef LFS_READONLY
static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
lfs_t *lfs = (lfs_t*)p;
lfs_block_t off = ((block - lfs->free.off)
+ lfs->cfg->block_count) % lfs->cfg->block_count;
if (off < lfs->free.size) {
lfs->free.buffer[off / 32] |= 1U << (off % 32);
}
return 0;
}
#endif
// indicate allocated blocks have been committed into the filesystem, this
// is to prevent blocks from being garbage collected in the middle of a
// commit operation
static void lfs_alloc_ack(lfs_t *lfs) {
lfs->free.ack = lfs->cfg->block_count;
}
// drop the lookahead buffer, this is done during mounting and failed
// traversals in order to avoid invalid lookahead state
static void lfs_alloc_drop(lfs_t *lfs) {
lfs->free.size = 0;
lfs->free.i = 0;
lfs_alloc_ack(lfs);
}
#ifndef LFS_READONLY
static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
while (true) {
while (lfs->free.i != lfs->free.size) {
lfs_block_t off = lfs->free.i;
lfs->free.i += 1;
lfs->free.ack -= 1;
if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
// found a free block
*block = (lfs->free.off + off) % lfs->cfg->block_count;
// eagerly find next off so an alloc ack can
// discredit old lookahead blocks
while (lfs->free.i != lfs->free.size &&
(lfs->free.buffer[lfs->free.i / 32]
& (1U << (lfs->free.i % 32)))) {
lfs->free.i += 1;
lfs->free.ack -= 1;
}
printf("debug: lfs_alloc: %x\n", *block);
return 0;
}
}
// check if we have looked at all blocks since last ack
if (lfs->free.ack == 0) {
LFS_ERROR("No more free space %"PRIu32,
lfs->free.i + lfs->free.off);
return LFS_ERR_NOSPC;
}
lfs->free.off = (lfs->free.off + lfs->free.size)
% lfs->cfg->block_count;
lfs->free.size = lfs_min(8*lfs->cfg->lookahead_size, lfs->free.ack);
lfs->free.i = 0;
// find mask of free blocks from tree
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
int err = lfs_fs_rawtraverse(lfs, lfs_alloc_lookahead, lfs, true);
if (err) {
lfs_alloc_drop(lfs);
return err;
}
}
}
#endif
/// Red-black-yellow Dhara tree operations ///
// helper functions
static bool lfsr_rbyd_isfetched(const lfsr_rbyd_t *rbyd) {
return !(rbyd->off == 0 && rbyd->trunk > 0);
}
// allocate an rbyd block
static int lfsr_rbyd_alloc(lfs_t *lfs, lfsr_rbyd_t *rbyd, uint32_t rev) {
*rbyd = (lfsr_rbyd_t){.rev=rev, .off=0, .trunk=0};
int err = lfs_alloc(lfs, &rbyd->block);
if (err) {
return err;
}
// TODO should erase be implicit in alloc eventually?
err = lfsr_bd_erase(lfs, rbyd->block);
if (err) {
return err;
}
return 0;
}
static int lfsr_rbyd_fetch(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfs_block_t block, lfs_size_t trunk,
lfsr_find_t *find) {
// clear any previous state in our find
if (find) {
find->predicted_id = -1;
find->predicted_tag = 0;
find->found_id = -1;
find->found_tag = 0;
}
// read the revision count and get the crc started
uint32_t rev;
uint32_t crc = 0;
int err = lfsr_bd_readcsum(lfs, block, 0, lfs->cfg->block_size,
&rev, sizeof(uint32_t),
&crc);
if (err) {
return err;
}
rev = lfs_fromle32_(&rev);
rbyd->block = block;
rbyd->off = 0;
rbyd->rev = rev;
// temporary state until we validate a crc
lfs_off_t off = sizeof(uint32_t);
lfs_off_t trunk_ = 0;
bool wastrunk = false;
lfs_size_t lower = 0;
lfs_size_t upper = 0;
lfs_size_t weight = 0;
// assume unerased until proven otherwise
lfsr_fcrc_t fcrc;
bool hasfcrc = false;
bool maybeerased = false;
// scan tags, checking valid bits, crcs, etc
while (off < lfs->cfg->block_size && (!trunk || rbyd->off <= trunk)) {
lfsr_tag_t tag;
lfs_size_t w;
lfs_size_t size;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
block, off, lfs->cfg->block_size,
&tag, &w, &size, &crc);
if (d < 0) {
if (d == LFS_ERR_INVAL || d == LFS_ERR_CORRUPT) {
maybeerased = maybeerased && d == LFS_ERR_INVAL;
break;
}
return d;
}
off += d;
// tag goes out of range?
if (!lfsr_tag_isalt(tag) && off + size > lfs->cfg->block_size) {
break;
}
// not an end-of-commit crc
if (!lfsr_tag_isalt(tag) && lfsr_tag_suptype(tag) != LFSR_TAG_CRC) {
// crc the entry, hopefully leaving it in the cache
err = lfsr_bd_csum(lfs, block, off, lfs->cfg->block_size, size,
&crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
// found an fcrc? save for later
if (tag == LFSR_TAG_FCRC) {
uint8_t buf[LFSR_FCRC_DSIZE];
err = lfsr_bd_read(lfs, block, off, lfs->cfg->block_size,
buf, lfs_min32(size, LFSR_FCRC_DSIZE));
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
lfs_ssize_t d = lfsr_fcrc_fromdisk(lfs, &fcrc,
LFSR_DATA_BUF(buf, lfs_min32(size, LFSR_FCRC_DSIZE)));
if (d < 0 && d != LFS_ERR_CORRUPT) {
return d;
}
// ignore malformed fcrcs
hasfcrc = (d != LFS_ERR_CORRUPT);
}
// is an end-of-commit crc
} else if (!lfsr_tag_isalt(tag)) {
uint32_t crc_ = 0;
err = lfsr_bd_read(lfs, block, off, lfs->cfg->block_size,
&crc_, sizeof(uint32_t));
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
crc_ = lfs_fromle32_(&crc_);
if (crc != crc_) {
// uh oh, crcs don't match
break;
}
// toss our crc into the filesystem seed for
// pseudorandom numbers, note we use another crc here
// as a collection function because it is sufficiently
// random and convenient
lfs->seed = lfs_crc32c(lfs->seed, &crc, sizeof(uint32_t));
// fcrc appears valid so far
maybeerased = hasfcrc;
hasfcrc = false;
// save what we've found so far
rbyd->off = off + size;
rbyd->crc = crc;
rbyd->trunk = trunk_;
rbyd->weight = weight;
if (find) {
find->found_id = find->predicted_id;
find->found_tag = find->predicted_tag;
}
}
// found a trunk of a tree?
if (lfsr_tag_istrunk(tag) && (!trunk || trunk >= off-d || wastrunk)) {
if (!wastrunk) {
// save trunk entry point
trunk_ = off-d;
// reset weights
lower = 0;
upper = 0;
wastrunk = true;
}
// derive the new weight of the tree from alt pointers
//
// NOTE we can't check for overflow/underflow here because we
// may be overeagerly parsing an invalid commit, it's ok for
// this to overflow/underflow as long as we throw it out later
// on a bad crc
if (lfsr_tag_isalt(tag)) {
if (lfsr_tag_isgt(tag)) {
upper += w;
} else {
lower += w;
}
} else {
lfs_ssize_t delta = (lower+upper+w) - weight;
weight = lower+upper+w;
lfs_ssize_t id = lower+w-1;
// adjust any pending finds
if (find && find->predicted_id >= (lfs_ssize_t)lower) {
// pending find removed?
if (find->predicted_id + delta < (lfs_ssize_t)lower) {
find->predicted_id = lower-1;
find->predicted_tag = 0;
} else {
find->predicted_id += delta;
}
}
// found our find request?
if (find && lfsr_tag_suptype(tag) == LFSR_TAG_NAME) {
// compare with disk
lfs_size_t d = lfs_min(size, find->name_size);
int cmp;
int err = lfsr_bd_cmp(lfs, block, off, d,
find->name, d,
&cmp);
if (err) {
return err;
}
if (cmp == 0) {
if (size < find->name_size) {
cmp = -1;
} else if (size > find->name_size) {
cmp = +1;
}
}
// found match?
if (cmp == 0) {
find->predicted_id = id;
find->predicted_tag = tag;
// didn't find a match, but found a better insertion point
} else if (cmp < 0 && id > find->predicted_id) {
find->predicted_id = id;
find->predicted_tag = 0;
}
}
// any non-alt terminates the current trunk
wastrunk = false;
}
}
if (!lfsr_tag_isalt(tag)) {
off += size;
}
}
// no valid commits?
if (rbyd->off == 0) {
return LFS_ERR_CORRUPT;
}
// did we end on a valid commit? we may have an erased block
bool erased = false;
if (maybeerased && rbyd->off % lfs->cfg->prog_size == 0) {
// check for an fcrc matching the next prog's erased state, if
// this failed most likely a previous prog was interrupted, we
// need a new erase
uint32_t fcrc_ = 0;
int err = lfsr_bd_csum(lfs, rbyd->block, rbyd->off, 0, fcrc.size,
&fcrc_);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// found beginning of erased part?
erased = (fcrc_ == fcrc.crc);
}
if (!erased) {
rbyd->off = lfs->cfg->block_size;
}
return 0;
}
static int lfsr_rbyd_lookupnext(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfs_ssize_t id, lfsr_tag_t tag,
lfs_ssize_t *id_, lfsr_tag_t *tag_, lfs_size_t *weight_,
lfsr_data_t *data_) {
// keep track of bounds as we descend down the tree
lfs_off_t branch = rbyd->trunk;
lfs_ssize_t lower = -1;
lfs_ssize_t upper = rbyd->weight;
// make sure we never look up zero tags, the way we create
// unreachable tags has a hole here
tag = lfs_max16(tag, 0x10);
// no trunk yet?
if (!branch) {
return LFS_ERR_NOENT;
}
// descend down tree
while (true) {
lfsr_tag_t alt;
lfs_size_t weight;
lfs_off_t jump;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
rbyd->block, branch, 0,
&alt, &weight, &jump, NULL);
if (d < 0) {
return d;
}
// found an alt?
if (lfsr_tag_isalt(alt)) {
if (lfsr_tag_follow(alt, weight, lower, upper, id, tag)) {
lfsr_tag_flip(&alt, &weight, lower, upper);
lfsr_tag_trim(alt, weight, &lower, &upper, NULL, NULL);
branch = branch - jump;
} else {
lfsr_tag_trim(alt, weight, &lower, &upper, NULL, NULL);
branch = branch + d;
}
// found end of tree?
} else {
// update the tag id
lfs_ssize_t id__ = upper-1;
lfsr_tag_t tag__ = alt;
// not what we're looking for?
if (id__ < id
|| (id__ == id && lfsr_tag_key(tag__) < lfsr_tag_key(tag))
|| lfsr_tag_isrm(tag__)) {
return LFS_ERR_NOENT;
}
// save what we found
// TODO how many of these need to be conditional?
if (id_) {
*id_ = id__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = id__ - lower;
}
if (data_) {
*data_ = LFSR_DATA_DISK(rbyd->block, branch + d, jump);
}
return 0;
}
}
}
static int lfsr_rbyd_lookup(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfs_ssize_t id, lfsr_tag_t tag,
lfsr_data_t *data_) {
lfs_ssize_t id_;
lfsr_tag_t tag_;
int err = lfsr_rbyd_lookupnext(lfs, rbyd, id, tag,
&id_, &tag_, NULL, data_);
if (err) {
return err;
}
// lookup finds the next-smallest tag, all we need to do is fail if it
// picks up the wrong tag
if (id_ != id || tag_ != tag) {
return LFS_ERR_NOENT;
}
return 0;
}
// TODO still need this?
// TODO move this into the tests?
static lfs_ssize_t lfsr_rbyd_get(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfs_ssize_t id, lfsr_tag_t tag, void *buffer, lfs_size_t size) {
lfsr_data_t data;
int err = lfsr_rbyd_lookup(lfs, rbyd, id, tag, &data);
if (err) {
return err;
}
return lfsr_data_read(lfs, data, 0, buffer, size);
}
// helper functions for managing the 3-element fifo used in lfsr_rbyd_append
static int lfsr_rbyd_p_flush(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_tag_t p_alts[static 3],
lfs_size_t p_weights[static 3],
lfs_off_t p_jumps[static 3],
unsigned count) {
// write out some number of alt pointers in our queue
for (unsigned i = 0; i < count; i++) {
if (p_alts[3-1-i]) {
// change to a relative jump at the last minute
lfsr_tag_t alt = p_alts[3-1-i];
lfs_size_t weight = p_weights[3-1-i];
lfs_off_t jump = rbyd->off - p_jumps[3-1-i];
lfs_ssize_t d = lfsr_bd_progtag(lfs, rbyd->block, rbyd->off,
alt, weight, jump,
&rbyd->crc);
if (d < 0) {
return d;
}
rbyd->off += d;
}
}
return 0;
}
static inline int lfsr_rbyd_p_push(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfsr_tag_t p_alts[static 3],
lfs_size_t p_weights[static 3],
lfs_off_t p_jumps[static 3],
lfsr_tag_t alt, lfs_ssize_t weight, lfs_off_t jump) {
int err = lfsr_rbyd_p_flush(lfs, rbyd, p_alts, p_weights, p_jumps, 1);
if (err) {
return err;
}
memmove(p_alts+1, p_alts, 2*sizeof(lfsr_tag_t));
memmove(p_weights+1, p_weights, 2*sizeof(lfs_size_t));
memmove(p_jumps+1, p_jumps, 2*sizeof(lfs_off_t));
p_alts[0] = alt;
p_weights[0] = weight;
p_jumps[0] = jump;
return 0;
}
static inline void lfsr_rbyd_p_pop(
lfsr_tag_t p_alts[static 3],
lfs_size_t p_weights[static 3],
lfs_off_t p_jumps[static 3]) {
memmove(p_alts, p_alts+1, 2*sizeof(lfsr_tag_t));
memmove(p_weights, p_weights+1, 2*sizeof(lfs_size_t));
memmove(p_jumps, p_jumps+1, 2*sizeof(lfs_off_t));
p_alts[2] = 0;
p_weights[2] = 0;
p_jumps[2] = 0;
}
static void lfsr_rbyd_p_red(
lfsr_tag_t p_alts[static 3],
lfs_size_t p_weights[static 3],
lfs_off_t p_jumps[static 3]) {
// propagate a red edge upwards
p_alts[0] = lfsr_tag_setblack(p_alts[0]);
if (p_alts[1]) {
p_alts[1] = lfsr_tag_setred(p_alts[1]);
// reorder so that top two edges always go in the same direction
if (lfsr_tag_isred(p_alts[2])) {
if (lfsr_tag_isparallel(p_alts[1], p_alts[2])) {
// no reorder needed
} else if (lfsr_tag_isparallel(p_alts[0], p_alts[2])) {
lfsr_tag_t alt_ = p_alts[1];
lfs_size_t weight_ = p_weights[1];
lfs_off_t jump_ = p_jumps[1];
p_alts[1] = lfsr_tag_setred(p_alts[0]);
p_weights[1] = p_weights[0];
p_jumps[1] = p_jumps[0];
p_alts[0] = lfsr_tag_setblack(alt_);
p_weights[0] = weight_;
p_jumps[0] = jump_;
} else if (lfsr_tag_isparallel(p_alts[0], p_alts[1])) {
lfsr_tag_t alt_ = p_alts[2];
lfs_size_t weight_ = p_weights[2];
lfs_off_t jump_ = p_jumps[2];
p_alts[2] = lfsr_tag_setred(p_alts[1]);
p_weights[2] = p_weights[1];
p_jumps[2] = p_jumps[1];
p_alts[1] = lfsr_tag_setred(p_alts[0]);
p_weights[1] = p_weights[0];
p_jumps[1] = p_jumps[0];
p_alts[0] = lfsr_tag_setblack(alt_);
p_weights[0] = weight_;
p_jumps[0] = jump_;
} else {
LFS_UNREACHABLE();
}
}
}
}
// core rbyd algorithm
static int lfsr_rbyd_append(lfs_t *lfs, lfsr_rbyd_t *rbyd,
lfs_ssize_t id, lfsr_tag_t tag, lfs_ssize_t delta,
lfsr_data_t data) {
// must fetch before mutating!
LFS_ASSERT(lfsr_rbyd_isfetched(rbyd));
// never write zero tags to disk, use unr if tag contains no data
LFS_ASSERT(tag != 0);
// we can't do anything if we're not erased
int err;
if (rbyd->off >= lfs->cfg->block_size) {
err = LFS_ERR_RANGE;
goto failed;
}
// ignore noops
if (lfsr_tag_setnomk(tag) == LFSR_TAG_UNR && delta == 0) {
return 0;
}
// make sure every rbyd starts with its revision count
if (rbyd->off == 0) {
uint8_t buf[sizeof(uint32_t)];
lfs_tole32_(rbyd->rev, &buf);
err = lfsr_bd_prog(lfs, rbyd->block, rbyd->off,
&buf, sizeof(uint32_t), &rbyd->crc);
if (err) {
goto failed;
}
rbyd->off += sizeof(uint32_t);
}
// figure out the range of tags we're operating on
//
// several lower bits are reserved, so we repurpose these
// to keep track of some append state
lfs_ssize_t id_;
lfs_ssize_t other_id_;
lfsr_tag_t tag_;
lfsr_tag_t other_tag_;
if (lfsr_tag_ismk(tag) && delta > 0) {
LFS_ASSERT(id <= (lfs_ssize_t)rbyd->weight);
// it's a bit ugly, but adjusting the id here makes the following
// logic work out more consistently
id -= 1;
id_ = id + 1;
other_id_ = id + 1;
// also note these tags MUST NOT be zero, due to unreachable tag holes
tag_ = 0x10;
other_tag_ = lfsr_tag_setupper(0x10);
} else if (lfsr_tag_ismk(tag) && delta < 0) {
LFS_ASSERT(id < (lfs_ssize_t)rbyd->weight);
// it's a bit ugly, but adjusting the id here makes the following
// logic work out more consistently
id += 1;
id_ = id - lfs_smax32(-delta, 0);
other_id_ = id;
// also note these tags MUST NOT be zero, due to unreachable tag holes
tag_ = 0x10;
other_tag_ = lfsr_tag_setupper(0x10);
} else if (lfsr_tag_isrm(tag)) {
LFS_ASSERT(id < (lfs_ssize_t)rbyd->weight);
id_ = id - lfs_smax32(-delta, 0);
other_id_ = id;
tag_ = lfsr_tag_key(tag);
other_tag_ = lfsr_tag_setupper(lfsr_tag_key(tag) + 0x10);
} else {
LFS_ASSERT(id < (lfs_ssize_t)rbyd->weight);
id_ = id - lfs_smax32(-delta, 0);
other_id_ = id;
tag_ = lfsr_tag_key(tag);
other_tag_ = lfsr_tag_setupper(lfsr_tag_key(tag));
}
// keep track of bounds as we descend down the tree
//
// this gets a bit confusing as we also may need to keep
// track of both the lower and upper bounds of diverging paths
// in the case of range deletions
lfs_off_t branch = rbyd->trunk;
lfs_ssize_t lower_id = -1;
lfs_ssize_t upper_id = rbyd->weight;
lfsr_tag_t lower_tag = 0;
lfsr_tag_t upper_tag = 0xffff;
// diverged state in case we are removing a range from the tree
//
// this is a second copy of the search path state, used to keep track
// of two search paths simulaneously when our range diverges.
//
// note we can't just perform two searches sequentially, or else our tree
// will end up very unbalanced.
lfs_off_t other_branch = 0;
lfs_ssize_t other_lower_id = 0;
lfs_ssize_t other_upper_id = 0;
lfsr_tag_t other_lower_tag = 0;
lfsr_tag_t other_upper_tag = 0;
// go ahead and update the rbyd's weight, if an error occurs our
// rbyd is no longer usable anyways
LFS_ASSERT(delta >= -(lfs_ssize_t)rbyd->weight);
rbyd->weight += delta;
// assume we'll update our trunk
rbyd->trunk = rbyd->off;
// no trunk yet?
if (!branch) {
goto leaf;
}
// queue of pending alts we can emulate rotations with
lfsr_tag_t p_alts[3] = {0, 0, 0};
lfs_size_t p_weights[3] = {0, 0, 0};
lfs_off_t p_jumps[3] = {0, 0, 0};
lfs_off_t graft = 0;
// descend down tree, building alt pointers
while (true) {
// read the alt pointer
lfsr_tag_t alt;
lfs_size_t weight;
lfs_off_t jump;
lfs_ssize_t d = lfsr_bd_readtag(lfs,
rbyd->block, branch, 0,
&alt, &weight, &jump, NULL);
if (d < 0) {
err = d;
goto failed;
}
// found an alt?
if (lfsr_tag_isalt(alt)) {
// make jump absolute
jump = branch - jump;
lfs_off_t branch_ = branch + d;
// do bounds want to take different paths? begin cutting
if (!lfsr_tag_hasdiverged(tag_)
&& lfsr_tag_follow2(alt, weight,
p_alts[0], p_weights[0],
lower_id, upper_id,
id_, tag_)
!= lfsr_tag_follow2(alt, weight,
p_alts[0], p_weights[0],
lower_id, upper_id,
other_id_, other_tag_)) {
// first take care of any lingering red alts
if (lfsr_tag_isred(p_alts[0])) {
alt = lfsr_tag_setblack(p_alts[0]);
weight = p_weights[0];
jump = p_jumps[0];
branch_ = branch;
lfsr_rbyd_p_pop(p_alts, p_weights, p_jumps);
} else {
tag_ = lfsr_tag_setdiverged(tag_);
other_tag_ = lfsr_tag_setdiverged(other_tag_);
other_branch = branch;
other_lower_id = lower_id;
other_upper_id = upper_id;
other_lower_tag = lower_tag;
other_upper_tag = upper_tag;
}
}
// if we're diverging, go ahead and make alt black, this isn't
// perfect but it's simpler and compact will take care of any
// balance issues that may occur
if (lfsr_tag_hasdiverged(tag_)) {
alt = lfsr_tag_setblack(alt);
}
// prune?
// <b >b
// .-'| .-'|
// <y | | |
// .-------'| | | |
// | <r | => | <b
// | .----' | .-----------|-'|
// | | <b | <b |
// | | .----'| | .----'| |
// 1 2 3 4 4 1 2 3 4 4 2
if (lfsr_tag_prune2(
alt, weight,
p_alts[0], p_weights[0],
lower_id, upper_id,
lower_tag, upper_tag)) {
if (lfsr_tag_isred(p_alts[0])) {
alt = lfsr_tag_setblack(p_alts[0]);
weight = p_weights[0];
branch_ = jump;
jump = p_jumps[0];
lfsr_rbyd_p_pop(p_alts, p_weights, p_jumps);
} else {
branch = jump;
continue;
}
}
// two reds makes a yellow, split?
if (lfsr_tag_isred(alt) && lfsr_tag_isred(p_alts[0])) {
LFS_ASSERT(lfsr_tag_isparallel(alt, p_alts[0]));
// if we take the red or yellow alt we can just point
// to the black alt
// <y >b
// .-------'| .-'|
// | <r | >b
// | .----'| => .-----|-'|
// | | <b | <b |
// | | .-'| | .-'| |
// 1 2 3 4 1 2 3 4 1
if (lfsr_tag_follow2(
alt, weight,
p_alts[0], p_weights[0],
lower_id, upper_id,
id_, tag_)) {
lfsr_tag_flip2(&alt, &weight,
p_alts[0], p_weights[0],
lower_id, upper_id);
lfs_swap32(&jump, &branch_);
lfs_swap16(&p_alts[0], &alt);
lfs_swap32(&p_weights[0], &weight);
lfs_swap32(&p_jumps[0], &jump);
alt = lfsr_tag_setblack(alt);
lfsr_tag_trim(
p_alts[0], p_weights[0],
&lower_id, &upper_id,
&lower_tag, &upper_tag);
lfsr_rbyd_p_red(p_alts, p_weights, p_jumps);
// otherwise we need to point to the yellow alt and
// prune later
// <b
// .-'|
// <y <y |
// .-------'| .-------'| |
// | <r => | <r |
// | .----'| | .----' |
// | | <b | | <b
// | | .-'| | | .----'|
// 1 2 3 4 1 2 3 4 4
} else {
LFS_ASSERT(graft != 0);
p_alts[0] = alt;
p_weights[0] += weight;
p_jumps[0] = graft;
lfsr_tag_trim(
p_alts[0], p_weights[0],
&lower_id, &upper_id,
&lower_tag, &upper_tag);
lfsr_rbyd_p_red(p_alts, p_weights, p_jumps);
branch = branch_;
continue;
}
}
// take black alt? needs a flip
// <b >b
// .-'| => .-'|
// 1 2 1 2 1
if (lfsr_tag_isblack(alt)
&& lfsr_tag_follow2(
alt, weight,
p_alts[0], p_weights[0],
lower_id, upper_id,
id_, tag_)) {
lfsr_tag_flip2(&alt, &weight,
p_alts[0], p_weights[0],
lower_id, upper_id);
lfs_swap32(&jump, &branch_);
}
// should've taken red alt? needs a flip
// <r >r
// .----'| .-'|
// | <b => | >b
// | .-'| .--|-'|
// 1 2 3 1 2 3 1
if (lfsr_tag_isred(p_alts[0])
&& lfsr_tag_follow(p_alts[0], p_weights[0],
lower_id, upper_id,
id_, tag_)) {
lfs_swap16(&p_alts[0], &alt);
lfs_swap32(&p_weights[0], &weight);
lfs_swap32(&p_jumps[0], &jump);
p_alts[0] = lfsr_tag_setred(p_alts[0]);
alt = lfsr_tag_setblack(alt);
lfsr_tag_flip2(&alt, &weight,
p_alts[0], p_weights[0],
lower_id, upper_id);
lfs_swap32(&jump, &branch_);
}
// trim alt from our current bounds
if (lfsr_tag_isblack(alt)) {
lfsr_tag_trim2(
alt, weight,
p_alts[0], p_weights[0],
&lower_id, &upper_id,
&lower_tag, &upper_tag);
}
// continue to next alt
graft = branch;
branch = branch_;
// prune inner alts if our tags diverged
if (lfsr_tag_hasdiverged(tag_)
&& lfsr_tag_isupper(tag_) != lfsr_tag_isgt(alt)) {
continue;
}
// push alt onto our queue
err = lfsr_rbyd_p_push(lfs, rbyd,
p_alts, p_weights, p_jumps,
alt, weight, jump);
if (err) {
goto failed;
}
// found end of tree?
} else {
// update the found tag/id
//
// note we:
// - preserve diverged bit (0x8)
// - preserve is upper tag (0x4)
// - set found tag (0x1)
tag_ = lfsr_tag_setfound(alt | (tag_ & 0xc));
id_ = upper_id-1;
// done?
if (!lfsr_tag_hasdiverged(tag_)
|| lfsr_tag_isfound(other_tag_)) {
break;
}
}
// switch to the other path if we have diverged
if (lfsr_tag_hasdiverged(tag_) || !lfsr_tag_isalt(alt)) {
lfs_swap16(&tag_, &other_tag_);
lfs_sswap32(&id_, &other_id_);
lfs_swap32(&branch, &other_branch);
lfs_sswap32(&lower_id, &other_lower_id);
lfs_sswap32(&upper_id, &other_upper_id);
lfs_swap16(&lower_tag, &other_lower_tag);
lfs_swap16(&upper_tag, &other_upper_tag);
}
}
// the last alt should always end up black
LFS_ASSERT(lfsr_tag_isblack(p_alts[0]));
// if we diverged, merge the bounds
LFS_ASSERT(lfsr_tag_isfound(tag_));
LFS_ASSERT(!lfsr_tag_hasdiverged(tag_)
|| lfsr_tag_isfound(other_tag_));
if (lfsr_tag_hasdiverged(tag_) && lfsr_tag_islower(tag_)) {
// finished on lower path
tag_ = other_tag_;
id_ = other_id_;
branch = other_branch;
upper_id = other_upper_id;
} else if (lfsr_tag_hasdiverged(tag_) && lfsr_tag_isupper(tag_)) {
// finished on upper path
lower_id = other_lower_id;
}
// split leaf nodes?
//
// note we bias the weights here so that lfsr_rbyd_lookupnext
// always finds the next biggest tag
lfsr_tag_t alt = 0;
lfs_size_t weight = 0;
if (lfsr_tag_isrm(tag_)) {
// found an old removed tag, no split needed, just prune the
// removed tag
} else if (id_ < id-lfs_smax32(-delta, 0)
|| (id_ == id-lfs_smax32(-delta, 0)
&& ((lfsr_tag_ismk(tag) && delta > 0)
|| lfsr_tag_key(tag_) < lfsr_tag_key(tag)))) {
if (lfsr_tag_isrm(tag)) {
// if removed make our tag unreachable
alt = LFSR_TAG_ALT(B, GT, 0);
weight = upper_id - lower_id - 1 + delta;
upper_id -= weight;
} else {
// split less than
alt = LFSR_TAG_ALT(R, LE, tag_);
weight = id_ - lower_id;
lower_id += weight;
}
} else if (id_ > id
|| (id_ == id
&& ((lfsr_tag_ismk(tag) && delta > 0)
|| lfsr_tag_key(tag_) > lfsr_tag_key(tag)))) {
if (lfsr_tag_isrm(tag)) {
// if removed make our tag unreachable
alt = LFSR_TAG_ALT(B, GT, 0);
weight = upper_id - lower_id - 1 + delta;
upper_id -= weight;
} else {
// split greater than
alt = LFSR_TAG_ALT(R, GT, tag);
weight = upper_id - id - 1;
upper_id -= weight;
}
}
if (alt) {
err = lfsr_rbyd_p_push(lfs, rbyd,
p_alts, p_weights, p_jumps,
alt, weight, branch);
if (err) {
goto failed;
}
if (lfsr_tag_isred(p_alts[0])) {
// introduce a red edge
lfsr_rbyd_p_red(p_alts, p_weights, p_jumps);
}
}
// flush any pending alts
err = lfsr_rbyd_p_flush(lfs, rbyd,
p_alts, p_weights, p_jumps, 3);
if (err) {
goto failed;
}
leaf:;
// write the actual tag
//
// note we always need something after the alts! without something between
// alts we may not be able to find the trunk of our tree
lfs_ssize_t d = lfsr_bd_progtag(lfs, rbyd->block, rbyd->off,
lfsr_tag_setnomk(tag), upper_id - lower_id - 1 + delta,
lfsr_data_size(data),
&rbyd->crc);
if (d < 0) {
err = d;
goto failed;
}
rbyd->off += d;
// don't forget the data!
err = lfsr_bd_progdata(lfs, rbyd->block, rbyd->off, data, &rbyd->crc);
if (err) {
goto failed;
}
rbyd->off += lfsr_data_size(data);
return 0;
failed:;
// if we fail mark the rbyd as unerased and release the pcache
lfs_cache_zero(lfs, &lfs->pcache);
rbyd->off = lfs->cfg->block_size;
return err;
}
static int lfsr_rbyd_commit(lfs_t *lfs, lfsr_rbyd_t *rbyd,
const lfsr_attr_t *attrs, lfs_size_t attr_count) {
// must fetch before mutating!
LFS_ASSERT(lfsr_rbyd_isfetched(rbyd));
// we can't do anything if we're not erased
int err;
if (rbyd->off >= lfs->cfg->block_size) {
err = LFS_ERR_RANGE;
goto failed;
}
// setup commit state
lfsr_rbyd_t rbyd_ = *rbyd;
// make sure every rbyd starts with its revision count
if (rbyd_.off == 0) {
uint8_t buf[sizeof(uint32_t)];
lfs_tole32_(rbyd_.rev, &buf);
err = lfsr_bd_prog(lfs, rbyd_.block, rbyd_.off,
&buf, sizeof(uint32_t), &rbyd_.crc);
if (err) {
goto failed;
}
rbyd_.off += sizeof(uint32_t);
}
// append each tag to the tree
for (lfs_size_t i = 0; i < attr_count; i++) {
err = lfsr_rbyd_append(lfs, &rbyd_,
attrs[i].id, attrs[i].tag, attrs[i].delta, attrs[i].data);
if (err) {
goto failed;
}
}
// align to the next prog unit
//
// this gets a bit complicated as we have two types of crcs:
//
// - 9-word crc with fcrc to check following prog (middle of block)
// - fcrc tag type => 2 byte le16
// - fcrc tag id => 1 byte leb128
// - fcrc tag size => 1 byte leb128 (worst case)
// - fcrc crc => 4 byte le32
// - fcrc size => 5 byte leb128 (worst case)
// - crc tag type => 2 byte le16
// - crc tag id => 1 byte leb128
// - crc tag size => 5 byte leb128 (worst case)
// - crc crc => 4 byte le32
// => 25 bytes total
//
// - 4-word crc with no following prog (end of block)
// - crc tag type => 2 byte le16
// - crc tag id => 1 byte leb128
// - crc tag size => 5 byte leb128 (worst case)
// - crc crc => 4 byte le32
// => 12 bytes total
//
lfs_off_t aligned = lfs_alignup(
rbyd_.off + 2+1+1+4+5 + 2+1+5+4,
lfs->cfg->prog_size);
// space for fcrc?
uint8_t perturb = 0;
if (aligned < lfs->cfg->block_size) {
// read the leading byte in case we need to change the expected
// value of the next tag's valid bit
int err = lfsr_bd_read(lfs, rbyd_.block, aligned, lfs->cfg->prog_size,
&perturb, 1);
if (err && err != LFS_ERR_CORRUPT) {
rbyd->off = lfs->cfg->block_size;
return err;
}
// find the expected fcrc, don't bother avoiding a reread of the
// perturb byte, as it should still be in our cache
lfsr_fcrc_t fcrc = {.size=lfs->cfg->prog_size, .crc=0};
err = lfsr_bd_csum(lfs, rbyd_.block, aligned, lfs->cfg->prog_size,
lfs->cfg->prog_size,
&fcrc.crc);
if (err && err != LFS_ERR_CORRUPT) {
goto failed;
}
uint8_t buf[LFSR_FCRC_DSIZE];
lfs_size_t d = lfsr_fcrc_todisk(lfs, &fcrc, buf);
lfs_ssize_t d_ = lfsr_bd_progtag(lfs, rbyd_.block, rbyd_.off,
LFSR_TAG_FCRC, 0, d,
&rbyd_.crc);
if (d_ < 0) {
err = d_;
goto failed;
}
rbyd_.off += d_;
err = lfsr_bd_prog(lfs, rbyd_.block, rbyd_.off,
buf, d, &rbyd_.crc);
if (err) {
goto failed;
}
rbyd_.off += d;
// at least space for a crc?
} else if (rbyd_.off + 2+1+5+4 <= lfs->cfg->block_size) {
// note this implicitly marks the rbyd as unerased
aligned = lfs->cfg->block_size;
// not even space for a crc? we can't finish the commit
} else {
err = LFS_ERR_RANGE;
goto failed;
}
// build end-of-commit crc
//
// note padding-size depends on leb-encoding depends on padding-size, to
// get around this catch-22 we just always write a fully-expanded leb128
// encoding
uint8_t buf[2+1+5+4];
lfs_tole16_(LFSR_TAG_CRC | (lfs_popc(rbyd_.crc) & 1), &buf[0]);
buf[2] = 0;
lfs_off_t padding = aligned - (rbyd_.off + 2+1+5);
buf[3] = 0x80 | (0x7f & (padding >> 0));
buf[4] = 0x80 | (0x7f & (padding >> 7));
buf[5] = 0x80 | (0x7f & (padding >> 14));
buf[6] = 0x80 | (0x7f & (padding >> 21));
buf[7] = 0x00 | (0x7f & (padding >> 28));
rbyd_.crc = lfs_crc32c(rbyd_.crc, buf, 2+1+5);
// we can't let the next tag appear as valid, so intentionally perturb the
// commit if this happens, note parity(crc(m)) == parity(m) with crc32c,
// so we can really change any bit to make this happen, we've reserved a bit
// in crc tags just for this purpose
if ((lfs_popc(rbyd_.crc) & 1) == (perturb & 1)) {
buf[0] ^= 0x10;
rbyd_.crc ^= 0x847609b4; // note crc(a ^ b) == crc(a) ^ crc(b)
}
lfs_tole32_(rbyd_.crc, &buf[2+1+5]);
err = lfsr_bd_prog(lfs, rbyd_.block, rbyd_.off, buf, 2+1+5+4, NULL);
if (err) {
goto failed;
}
rbyd_.off += 2+1+5+4;
// flush our caches, finalizing the commit on-disk
err = lfsr_bd_sync(lfs);
if (err) {
goto failed;
}
// succesful commit, check checksum to make sure
uint32_t crc_ = rbyd->crc;
err = lfsr_bd_csum(lfs, rbyd_.block, rbyd->off, 0,
rbyd_.off-4 - rbyd->off,
&crc_);
if (err) {
goto failed;
}
if (rbyd_.crc != crc_) {
// oh no, something went wrong
LFS_ERROR("Rbyd corrupted during commit "
"(block=0x%"PRIx32", 0x%08"PRIx32" != 0x%08"PRIx32")",
rbyd_.block, rbyd_.crc, crc_);
err = LFS_ERR_CORRUPT;
goto failed;
}
// ok, everything is good, save what we've committed
rbyd_.off = aligned;
*rbyd = rbyd_;
return 0;
failed:;
// if we fail mark the rbyd as unerased and release the pcache
lfs_cache_zero(lfs, &lfs->pcache);
rbyd->off = lfs->cfg->block_size;
return err;
}
// the following are mostly btree helpers, but since they operate on rbyds,
// exist in the rbyd namespace
static int lfsr_rbyd_cutoff(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
lfs_ssize_t cutoff) {
// determine if there are fewer than "cutoff" unique ids in the rbyd,
// this is used to determine if the underlying rbyd is degenerate and can
// be reverted to an inlined btree
//
// note cutoff is expected to be quite small, <= 2, so we should make sure
// to exit our traverse early
// cutoff=-1 => no cutoff
if (cutoff < 0) {
return false;
}
// count ids until we exceed our cutoff
lfs_ssize_t id = -1;
lfs_size_t count = 0;
while (true) {
int err = lfsr_rbyd_lookupnext(lfs, rbyd, id+1, 0,
&id, NULL, NULL, NULL);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
return true;
}
count += 1;
if (count > (lfs_size_t)cutoff) {
return false;
}
}
}
/// Rbyd b-tree operations ///
// convenience operations
// TODO need null btrees?
#define LFSR_BTREE_NULL ((lfsr_btree_t){.weight=0x80000000})
static inline bool lfsr_btree_isinlined(const lfsr_btree_t *btree) {
return btree->weight & 0x80000000;
}
static inline bool lfsr_btree_isnull(const lfsr_btree_t *btree) {
return lfsr_btree_isinlined(btree) && btree->inlined.tag == 0;
}
static inline lfs_size_t lfsr_btree_weight(const lfsr_btree_t *btree) {
return btree->weight & 0x7fffffff;
}
static inline lfs_size_t lfsr_btree_setinlined(lfs_size_t weight) {
return weight | 0x80000000;
}
// branch on-disk encoding
// 3 leb128 + 1 crc32c => 19 bytes (worst case)
#define LFSR_BRANCH_DSIZE (5+5+5+4)
static lfs_ssize_t lfsr_branch_todisk(lfs_t *lfs, const lfsr_rbyd_t *branch,
uint8_t buffer[static LFSR_BRANCH_DSIZE]) {
(void)lfs;
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfs_toleb128(branch->weight, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfs_toleb128(branch->trunk, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfs_toleb128(branch->block, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
lfs_tole32_(branch->crc, &buffer[d]);
d += 4;
return d;
}
static lfs_ssize_t lfsr_branch_fromdisk(lfs_t *lfs, lfsr_rbyd_t *branch,
lfsr_data_t data) {
// setting off to 0 here will trigger asserts if we try to append
// without fetching first
branch->off = 0;
lfs_ssize_t d = 0;
lfs_ssize_t d_ = lfsr_data_readleb128(lfs, data, d, &branch->weight);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfsr_data_readleb128(lfs, data, d, &branch->trunk);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfsr_data_readleb128(lfs, data, d, &branch->block);
if (d_ < 0) {
return d_;
}
d += d_;
d_ = lfsr_data_readle32(lfs, data, d, &branch->crc);
if (d_ < 0) {
return d_;
}
d += d_;
return d;
}
// btree on-disk encoding
//
// note we leave disambiguating inlined/non-inlined btrees up to the caller
#define LFSR_BTREE_DSIZE ( \
LFSR_BRANCH_DSIZE > LFSR_BTREE_INLINESIZE \
? LFSR_BRANCH_DSIZE \
: LFSR_BTREE_INLINESIZE)
static lfs_ssize_t lfsr_btree_todisk(lfs_t *lfs, const lfsr_btree_t *btree,
lfsr_tag_t *tag_, uint8_t buffer[static LFSR_BTREE_DSIZE]) {
// we shouldn't write null btrees to disk, we just don't write out btrees
// if they're null
LFS_ASSERT(!lfsr_btree_isnull(btree));
// inlined?
if (lfsr_btree_isinlined(btree)) {
*tag_ = btree->inlined.tag;
memcpy(buffer, btree->inlined.buffer, btree->inlined.size);
return btree->inlined.size;
// not inlined
} else {
*tag_ = LFSR_TAG_BRANCH;
return lfsr_branch_todisk(lfs, &btree->root, buffer);
}
}
// TODO wait we actually need to store the weight on-disk for btrees
static lfs_ssize_t lfsr_btree_fromdisk(lfs_t *lfs, lfsr_btree_t *btree,
lfsr_tag_t tag, lfs_size_t weight, lfsr_data_t data) {
// inlined?
if (tag != LFSR_TAG_BRANCH) {
btree->weight = lfsr_btree_setinlined(weight);
btree->inlined.tag = tag;
lfs_ssize_t size = lfsr_data_read(lfs, data, 0,
btree->inlined.buffer, LFSR_BTREE_INLINESIZE);
if (size < 0) {
return size;
}
btree->inlined.size = size;
return size;
// not inlined
} else {
return lfsr_branch_fromdisk(lfs, &btree->root, data);
}
}
// B-tree operations
// TODO should there be a different lfsr_btree_lookupnext without rbyd_/rid_?
static int lfsr_btree_lookupnext(lfs_t *lfs,
const lfsr_btree_t *btree, lfs_size_t bid,
lfs_size_t *bid_, lfsr_rbyd_t *rbyd_, lfs_ssize_t *rid_,
lfsr_tag_t *tag_, lfs_size_t *weight_,
lfsr_data_t *data_, bool validate) {
// in range?
if (bid >= lfsr_btree_weight(btree)) {
return LFS_ERR_NOENT;
}
// inlined?
if (lfsr_btree_isinlined(btree)) {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = lfsr_btree_weight(btree)-1;
}
if (tag_) {
*tag_ = btree->inlined.tag;
}
if (weight_) {
*weight_ = lfsr_btree_weight(btree);
}
if (data_) {
*data_ = LFSR_DATA_BUF(btree->inlined.buffer, btree->inlined.size);
}
return 0;
}
// descend down the btree looking for our bid
lfsr_rbyd_t branch = btree->root;
lfs_ssize_t rid = bid;
while (true) {
// if we're validating during our lookup, we need to fetch each branch,
// otherwise we can get away with assuming our stored block+trunk is
// correct
//
// though we assume fetched branches have already been validated, this
// generally only affects the root rbyd but note the root rbyd is the
// most heavily accessed
//
if (validate && !lfsr_rbyd_isfetched(&branch)) {
lfsr_rbyd_t branch_;
int err = lfsr_rbyd_fetch(lfs, &branch_,
branch.block, branch.trunk, NULL);
if (err) {
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Corrupted rbyd found during btree lookup "
"(rbyd=0x%"PRIx32".%"PRIx32", "
"0x%08"PRIx32" != 0x%08"PRIx32")",
branch.block, branch.trunk,
branch_.crc, branch.crc);
}
return err;
}
// test that our branch's crc matches what's expected
//
// it should be noted it's very unlikely for this to be hit without
// the above fetch failing since it includes both an internal
// crc check and trunk check
if (branch_.crc != branch.crc) {
LFS_ERROR("Corrupted rbyd found during btree lookup "
"(rbyd=0x%"PRIx32".%"PRIx32", "
"0x%08"PRIx32" != 0x%08"PRIx32")",
branch.block, branch.trunk,
branch_.crc, branch.crc);
return LFS_ERR_CORRUPT;
}
LFS_ASSERT(branch_.trunk == branch.trunk);
LFS_ASSERT(branch_.weight == branch.weight);
branch = branch_;
}
// each branch is a pair of optional name + on-disk structure
lfs_ssize_t rid__;
lfsr_tag_t tag__;
// TODO do we really need to fetch weight__ if we get it in our
// btree struct?
// TODO maybe only when validating?
lfs_size_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, &branch, rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
if (lfsr_tag_suptype(tag__) == LFSR_TAG_NAME) {
err = lfsr_rbyd_lookupnext(lfs, &branch, rid__, LFSR_TAG_STRUCT,
NULL, &tag__, NULL, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// found another branch
if (tag__ == LFSR_TAG_BRANCH) {
// adjust rid with subtree's weight
rid -= (rid__ - (weight__-1));
// fetch the next branch
lfs_ssize_t d = lfsr_branch_fromdisk(lfs, &branch, data__);
if (d < 0) {
return d;
}
LFS_ASSERT(branch.weight == weight__);
// found our bid
} else {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = bid + (rid__ - rid);
}
if (rbyd_) {
*rbyd_ = branch;
}
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return 0;
}
}
}
static int lfsr_btree_lookup(lfs_t *lfs,
const lfsr_btree_t *btree, lfs_size_t bid,
lfsr_tag_t *tag_, lfs_size_t *weight_,
lfsr_data_t *data_, bool validate) {
lfs_size_t bid_;
int err = lfsr_btree_lookupnext(lfs, btree, bid,
&bid_, NULL, NULL, tag_, weight_, data_,
validate);
if (err) {
return err;
}
// lookup finds the next-smallest bid, all we need to do is fail if it
// picks up the wrong bid
if (bid_ != bid) {
return LFS_ERR_NOENT;
}
return 0;
}
// TODO still need this?
// TODO move this into the tests?
static int lfsr_btree_get(lfs_t *lfs,
const lfsr_btree_t *btree, lfs_size_t bid,
lfsr_tag_t *tag_, lfs_size_t *weight_,
void *buffer, lfs_size_t size,
bool validate) {
lfsr_data_t data;
int err = lfsr_btree_lookup(lfs, btree, bid,
tag_, weight_, &data,
validate);
if (err) {
return err;
}
return lfsr_data_read(lfs, data, 0, buffer, size);
}
// TODO should lfsr_btree_lookupnext/lfsr_btree_parent be deduplicated?
static int lfsr_btree_parent(lfs_t *lfs,
const lfsr_btree_t *btree, lfs_size_t bid, const lfsr_rbyd_t *child,
lfsr_rbyd_t *rbyd_, lfs_ssize_t *rid_) {
// inlined? root?
if (bid >= lfsr_btree_weight(btree)
|| lfsr_btree_isinlined(btree)
|| (btree->root.block == child->block
&& btree->root.trunk == child->trunk)) {
return LFS_ERR_NOENT;
}
// descend down the btree looking for our id
lfsr_rbyd_t branch = btree->root;
lfs_ssize_t rid = bid;
while (true) {
// each branch is a pair of optional name + on-disk structure
lfs_ssize_t rid__;
lfsr_tag_t tag__;
// TODO do we really need to fetch weight__ if we get it in our
// btree struct?
// TODO maybe only when validating?
lfs_size_t weight__;
lfsr_data_t data__;
int err = lfsr_rbyd_lookupnext(lfs, &branch, rid, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
if (lfsr_tag_suptype(tag__) == LFSR_TAG_NAME) {
err = lfsr_rbyd_lookupnext(lfs, &branch, rid__, LFSR_TAG_STRUCT,
NULL, &tag__, NULL, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// didn't find our child?
if (tag__ != LFSR_TAG_BRANCH) {
return LFS_ERR_NOENT;
}
// adjust rid with subtree's weight
rid -= (rid__ - (weight__-1));
// fetch the next branch
lfsr_rbyd_t branch_;
lfs_ssize_t d = lfsr_branch_fromdisk(lfs, &branch_, data__);
if (d < 0) {
return d;
}
LFS_ASSERT(branch_.weight == weight__);
// found our child?
if (branch_.block == child->block && branch_.trunk == child->trunk) {
// TODO how many of these should be conditional?
if (rbyd_) {
*rbyd_ = branch;
}
if (rid_) {
*rid_ = rid__;
}
return 0;
}
branch = branch_;
}
}
static lfs_ssize_t lfsr_btree_namelookupnext(lfs_t *lfs,
const lfsr_btree_t *btree, const char *name, lfs_size_t name_size,
lfs_size_t *bid_, lfsr_rbyd_t *rbyd_, lfs_ssize_t *rid_,
lfsr_tag_t *tag_, lfs_size_t *weight_, lfsr_data_t *data_) {
// an empty tree?
if (lfsr_btree_weight(btree) == 0) {
return LFS_ERR_NOENT;
}
// inlined?
if (lfsr_btree_isinlined(btree)) {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = lfsr_btree_weight(btree)-1;
}
if (tag_) {
*tag_ = btree->inlined.tag;
}
if (weight_) {
*weight_ = lfsr_btree_weight(btree);
}
if (data_) {
*data_ = LFSR_DATA_BUF(btree->inlined.buffer, btree->inlined.size);
}
return 0;
}
// descend down the btree looking for our name
lfsr_rbyd_t branch = btree->root;
lfs_ssize_t bid = 0;
lfsr_find_t find = {.name=name, .name_size=name_size};
while (true) {
// name lookup in our rbyds requires a linear search, so we might as
// well revalidate the rbyd with a fetch
lfsr_rbyd_t branch_;
int err = lfsr_rbyd_fetch(lfs, &branch_,
branch.block, branch.trunk, &find);
if (err) {
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Corrupted rbyd found during btree lookup "
"(rbyd=0x%"PRIx32".%"PRIx32", "
"0x%08"PRIx32" != 0x%08"PRIx32")",
branch.block, branch.trunk,
branch_.crc, branch.crc);
}
return err;
}
if (branch_.crc != branch.crc) {
LFS_ERROR("Corrupted rbyd found during btree lookup "
"(rbyd=0x%"PRIx32".%"PRIx32", "
"0x%08"PRIx32" != 0x%08"PRIx32")",
branch.block, branch.trunk,
branch_.crc, branch.crc);
return LFS_ERR_CORRUPT;
}
LFS_ASSERT(branch_.trunk == branch.trunk);
LFS_ASSERT(branch_.weight == branch.weight);
branch = branch_;
// assume lowest id if no name found
//
// note this ignore any name attached to the lowest id, this is
// intentional as allowing for "vestigial" names in our blocks helps
// simplify some of the more complicated merge/split interactions
if (find.found_id < 0) {
find.found_id = 0;
}
// the find may not match exactly, but it will indicate which id we
// should follow
//
// Note that we can't reliably find the weight in fetch. If, during our
// linear search, we match an id that is later deleted, we know id-1
// should be the new id, but we don't have enough information to
// determine the new weight. So unfortunately we need an additional
// lookup to find the weight.
lfsr_tag_t tag__;
lfs_ssize_t rid__;
// TODO do we really need to fetch weight__ if we get it in our
// btree struct?
// TODO maybe only when validating?
lfs_size_t weight__;
lfsr_data_t data__;
err = lfsr_rbyd_lookupnext(lfs, &branch, find.found_id, 0,
&rid__, &tag__, &weight__, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
if (lfsr_tag_suptype(tag__) == LFSR_TAG_NAME) {
err = lfsr_rbyd_lookupnext(lfs, &branch, rid__, LFSR_TAG_STRUCT,
NULL, &tag__, NULL, &data__);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// found another branch
if (tag__ == LFSR_TAG_BRANCH) {
// update our id
bid += rid__-(weight__-1);
// fetch the next branch
lfs_ssize_t d = lfsr_branch_fromdisk(lfs, &branch, data__);
if (d < 0) {
return d;
}
LFS_ASSERT(branch.weight == weight__);
// found our id
} else {
// TODO how many of these should be conditional?
if (bid_) {
*bid_ = bid + rid__;
}
if (rbyd_) {
*rbyd_ = branch;
}
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return 0;
}
}
}
// we need some scratch space for tail-recursive attr in lfsr_btree_commit
//
// note this is a mix of attributes and their payloads
// note also we need this to be a const expression since it's used in
// array allocations
#define LFSR_BTREE_SCRATCHATTRS ( \
4 \
+ ((2*LFSR_BRANCH_DSIZE) + sizeof(lfsr_attr_t)-1) \
/ sizeof(lfsr_attr_t))
// this macro creates an attr list with enough reserved space for
// btree commit operations, it's ugly but likely any implementation
// of this will look ugly since we can't use things like lfs_min32 in
// an array declaration
#define LFSR_BTREE_ATTRS(...) \
(lfsr_attr_t[ \
sizeof((lfsr_attr_t[]){__VA_ARGS__}) / sizeof(lfsr_attr_t) \
> LFSR_BTREE_SCRATCHATTRS \
? sizeof((lfsr_attr_t[]){__VA_ARGS__}) / sizeof(lfsr_attr_t) \
: LFSR_BTREE_SCRATCHATTRS \
]){__VA_ARGS__}, \
sizeof((lfsr_attr_t[]){__VA_ARGS__}) / sizeof(lfsr_attr_t)
// core btree algorithm
static int lfsr_btree_commit(lfs_t *lfs,
lfsr_btree_t *btree, lfs_size_t bid, lfs_ssize_t cutoff,
lfsr_rbyd_t *rbyd,
lfsr_attr_t attrs[static LFSR_BTREE_SCRATCHATTRS],
lfs_size_t attr_count) {
// other layers should check for inlined btrees before this
LFS_ASSERT(!lfsr_btree_isinlined(btree));
while (true) {
// we will always need our parent, so go ahead and find it
lfsr_rbyd_t parent;
lfs_ssize_t pid;
int err = lfsr_btree_parent(lfs, btree, bid, rbyd, &parent, &pid);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
// mark pid as -1 if we have no parent
pid = -1;
}
lfs_size_t pweight = rbyd->weight;
// fetch our rbyd so we can mutate it
//
// note that some paths lead this to being a newly allocated rbyd, these
// will fail to fetch so we need to check that this rbyd is unfetched
//
// a strange benefit is we cache the root of our btree this way
if (!lfsr_rbyd_isfetched(rbyd)) {
err = lfsr_rbyd_fetch(lfs, rbyd, rbyd->block, rbyd->trunk, NULL);
if (err) {
return err;
}
}
// is rbyd erased? can we sneak our commit into any remaining
// erased bytes? note that the btree limit prevents this from mutating
// other references to the rbyd
err = lfsr_rbyd_commit(lfs, rbyd, attrs, attr_count);
if (err && err != LFS_ERR_RANGE) {
// TODO wait should we also move if there is corruption here?
return err;
}
// can't commit, try to compact
lfsr_rbyd_t rbyd_;
lfs_size_t lower_dsize = 0;
if (err) {
// first check if we are a degenerate root and can be reverted to
// an inlined btree
//
// This gets a bit weird since we're defering our pending
// attributes to after the compaction. When we can/can't be inlined
// depends on those attributes, but trying to evaluate attributes
// is complicated and expensive.
//
// Instead we just let the upper layers indicate a cutoff for when
// an rbyd can be inlined, and leave the inlining work up to the
// upper layers.
if (pid == -1) {
int degenerate = lfsr_rbyd_cutoff(lfs, rbyd, cutoff);
if (degenerate) {
return degenerate;
}
}
// TODO were we doing something funky with rev?
// allocate a new rbyd
err = lfsr_rbyd_alloc(lfs, &rbyd_, rbyd->rev+1);
if (err) {
return err;
}
// try to copy over ids
lfs_ssize_t id = 0;
lfsr_tag_t tag = 0;
while (true) {
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, rbyd, id, lfsr_tag_next(tag),
&id, &tag, NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// Because it makes a lot of the split-sensitive cross-id
// operations easier, we can end up with an occasional
// "vestigial" name tag on the first id in a block. We make
// sure to ignore these during lookup, but it would be more
// complicated then it's worth to clean these up proactively.
//
// Discarding these during compaction is easy and prevents any
// real storage cost.
if (lfsr_tag_suptype(tag) == LFSR_TAG_NAME
&& rbyd_.weight == 0) {
continue;
}
// note we need to account for the missing weight of vestigial
// name tags in the following branch tag, which is why we
// calculate weight like this
lfs_size_t w = id+1 - rbyd_.weight;
// keep track of worst-case encoding size in case we need to
// split
lower_dsize += LFSR_TAG_DSIZE + lfsr_data_size(data);
// append the attr
err = lfsr_rbyd_append(lfs, &rbyd_,
id-lfs_smax32(w-1, 0), lfsr_tag_setmk(tag), +w,
data);
if (err) {
return err;
}
// keep rbyd < our compaction threshold (1/2) to avoid
// degenerate cases
if (rbyd_.off > lfs->cfg->block_size/2) {
goto split;
}
}
// append any pending attrs, it's up to upper
// layers to make sure these always fit
for (lfs_size_t i = 0; i < attr_count; i++) {
err = lfsr_rbyd_append(lfs, &rbyd_,
attrs[i].id, attrs[i].tag, attrs[i].delta,
attrs[i].data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
// is our compacted size too small? try to merge with one of
// our siblings
if (rbyd_.off < lfs->cfg->block_size/4) {
goto merge;
merge_abort:;
}
// finalize commit
err = lfsr_rbyd_commit(lfs, &rbyd_, NULL, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
*rbyd = rbyd_;
}
// done?
if (pid == -1) {
break;
}
// cannibalize some attributes in our attr list to store
// our branch
uint8_t *scratch_buf = (uint8_t*)&attrs[2];
lfs_ssize_t d = lfsr_branch_todisk(lfs, rbyd, scratch_buf);
if (d < 0) {
return d;
}
// prepare commit to parent, tail recursing upwards
//
// note that since we defer merges to compaction time, we can
// end up removing an rbyd here
if (rbyd->weight == 0) {
attrs[0] = LFSR_ATTR(pid, MKUNR, +rbyd->weight-pweight,
scratch_buf, d);
attr_count = 1;
} else {
attrs[0] = LFSR_ATTR(pid, UNR, +rbyd->weight-pweight, NULL, 0);
attrs[1] = LFSR_ATTR(pid+rbyd->weight-pweight, BRANCH, 0,
scratch_buf, d);
attr_count = 2;
}
*rbyd = parent;
cutoff = -1;
continue;
split:;
// first figure out which id we need to split around
//
// here we use the worst-case disk encoding as a heuristic, since
// this translates roughly into the storage cost of each id, which
// we need to keep evenly distributed across blocks in our btree
//
// we can keep track of the disk encoding for the tags we've seen, but
// need to also read the disk encoding of tags we haven't seen. If we
// do this backwards, we can do this in 1/2 an additional pass.
//
// note this is the most expensive operation in lfsr_btree_commit
//
lfs_ssize_t id = rbyd->weight-1;
lfs_size_t split_id = rbyd_.weight;
lfs_size_t upper_dsize = 0;
while (true) {
lfsr_tag_t tag = 0;
lfs_size_t w = 0;
lfs_size_t dsize = 0;
while (true) {
lfs_ssize_t id_;
lfs_size_t w_;
lfsr_data_t data;
int err = lfsr_rbyd_lookupnext(lfs, rbyd,
id, lfsr_tag_next(tag),
&id_, &tag, &w_, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT || id_ != id) {
break;
}
// keep track of weight to iterate backwards
w += w_;
// assume worst-case encoding size
dsize += LFSR_TAG_DSIZE + lfsr_data_size(data);
}
LFS_ASSERT(w > 0);
// steal dsize from lower_dsize if we start overlapping
if ((lfs_size_t)id-(w-1) < split_id) {
split_id = id-(w-1);
lower_dsize -= dsize;
}
upper_dsize += dsize;
// done when upper/lower dsizes are close to balanced
//
// but we also make sure at least one id is removed, in case our
// compact did not terminate on a clean id boundary
//
if (upper_dsize >= lower_dsize && split_id < rbyd_.weight) {
break;
}
// iterate backwards
id -= w;
}
// we should have _some_ ids in both children
LFS_ASSERT(split_id > 0);
LFS_ASSERT(split_id < rbyd->weight);
// we can keep our attempted compact, we just need to remove any
// ids that belong in the sibling
LFS_ASSERT(split_id < rbyd_.weight);
err = lfsr_rbyd_append(lfs, &rbyd_,
rbyd_.weight-1, LFSR_TAG_MKUNR, -(rbyd_.weight-split_id),
LFSR_DATA_NULL);
if (err) {
return err;
}
// commit pending attrs, these may need to go into both rbyds,
// upper layers should make sure this can't fail by limiting the
// maximum commit size
// TODO filter-like tag? "from" but from device?
lfs_size_t split_id_ = split_id;
for (lfs_size_t i = 0; i < attr_count; i++) {
if (attrs[i].id < (lfs_ssize_t)split_id_) {
err = lfsr_rbyd_append(lfs, &rbyd_,
attrs[i].id, attrs[i].tag, attrs[i].delta,
attrs[i].data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
// we need to make sure we keep split_id updated with weight changes
if (attrs[i].id < (lfs_ssize_t)split_id_) {
split_id_ += attrs[i].delta;
}
}
// finalize commit
err = lfsr_rbyd_commit(lfs, &rbyd_, NULL, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// create a sibling and copy remaining ids there, upper layers
// should make sure this can't fail by limiting the maximum
// commit size
lfsr_rbyd_t sibling;
err = lfsr_rbyd_alloc(lfs, &sibling, rbyd->rev+1);
if (err) {
return err;
}
id = split_id;
lfsr_tag_t tag = 0;
while (true) {
lfs_size_t w;
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, rbyd, id, lfsr_tag_next(tag),
&id, &tag, &w, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// append the attr
err = lfsr_rbyd_append(lfs, &sibling,
id-split_id-lfs_smax32(w-1, 0), lfsr_tag_setmk(tag), +w,
data);
if (err) {
return err;
}
}
// commit pending attrs, these may need to go into both rbyds,
// upper layers should make sure this can't fail by limiting the
// maximum commit size
split_id_ = split_id;
for (lfs_size_t i = 0; i < attr_count; i++) {
if (attrs[i].id >= (lfs_ssize_t)split_id_) {
err = lfsr_rbyd_append(lfs, &sibling,
attrs[i].id-split_id_, attrs[i].tag, attrs[i].delta,
attrs[i].data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
// we need to make sure we keep split_id updated with weight changes
if (attrs[i].id < (lfs_ssize_t)split_id_) {
split_id_ += attrs[i].delta;
}
}
// finalize commit
err = lfsr_rbyd_commit(lfs, &sibling, NULL, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// lookup first name in sibling to use as the split name
//
// note we need to do this after playing out pending attrs in case
// they introduce a new name!
lfsr_tag_t stag;
lfsr_data_t sdata;
err = lfsr_rbyd_lookupnext(lfs, &sibling, 0, LFSR_TAG_NAME,
NULL, &stag, NULL, &sdata);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// cannibalize some attributes in our attr list to store
// our branches
uint8_t *scratch_buf1 = (uint8_t*)&attrs[4];
uint8_t *scratch_buf2 = (uint8_t*)&attrs[4] + LFSR_BRANCH_DSIZE;
lfs_ssize_t d1 = lfsr_branch_todisk(lfs, &rbyd_, scratch_buf1);
if (d1 < 0) {
return d1;
}
lfs_ssize_t d2 = lfsr_branch_todisk(lfs, &sibling, scratch_buf2);
if (d2 < 0) {
return d2;
}
// no parent? introduce a new trunk
if (pid == -1) {
int err = lfsr_rbyd_alloc(lfs, &parent, 1);
if (err) {
return err;
}
// prepare commit to parent, tail recursing upwards
attrs[0] = LFSR_ATTR(0, MKBRANCH, +rbyd_.weight,
scratch_buf1, d1);
attrs[1] = (lfsr_tag_suptype(stag) == LFSR_TAG_NAME
? LFSR_ATTR_DATA(rbyd_.weight, MKBNAME, +sibling.weight,
sdata)
: LFSR_ATTR_NOOP);
attrs[2] = (lfsr_tag_suptype(stag) == LFSR_TAG_NAME
? LFSR_ATTR(0+rbyd_.weight+sibling.weight-1, BRANCH, 0,
scratch_buf2, d2)
: LFSR_ATTR(0+rbyd_.weight, MKBRANCH, +sibling.weight,
scratch_buf2, d2));
attr_count = 3;
// yes parent? push up split
} else {
// prepare commit to parent, tail recursing upwards
attrs[0] = LFSR_ATTR(pid, UNR, +rbyd_.weight-pweight, NULL, 0);
attrs[1] = LFSR_ATTR(pid-(pweight-1)+rbyd_.weight-1, BRANCH, 0,
scratch_buf1, d1);
attrs[2] = (lfsr_tag_suptype(stag) == LFSR_TAG_NAME
? LFSR_ATTR_DATA(pid-(pweight-1)+rbyd_.weight,
MKBNAME, +sibling.weight,
sdata)
: LFSR_ATTR_NOOP);
attrs[3] = (lfsr_tag_suptype(stag) == LFSR_TAG_NAME
? LFSR_ATTR(pid-(pweight-1)+rbyd_.weight+sibling.weight-1,
BRANCH, 0,
scratch_buf2, d2)
: LFSR_ATTR(pid-(pweight-1)+rbyd_.weight,
MKBRANCH, +sibling.weight,
scratch_buf2, d2));
attr_count = 4;
}
*rbyd = parent;
cutoff = -1;
continue;
merge:;
// no parent? can't merge
if (pid == -1) {
goto merge_abort;
}
// only child? can't merge
if (pweight == parent.weight) {
goto merge_abort;
}
// last child? try the left sibling
lfs_ssize_t sid;
lfs_ssize_t sdelta;
if ((lfs_size_t)pid == parent.weight-1) {
sid = pid-pweight;
sdelta = 0;
// not last child? try the right sibling
} else {
sid = pid+1;
sdelta = rbyd_.weight;
}
// try looking up the sibling
// TODO do we really need to fetch sweight if we get it in our
// btree struct?
lfs_size_t sweight;
err = lfsr_rbyd_lookupnext(lfs, &parent, sid, LFSR_TAG_NAME,
&sid, &stag, &sweight, &sdata);
if (err) {
// no sibling? can't merge
if (err == LFS_ERR_NOENT) {
goto merge_abort;
}
return err;
}
if (stag == LFSR_TAG_NAME) {
err = lfsr_rbyd_lookupnext(lfs, &parent, sid, LFSR_TAG_STRUCT,
NULL, &stag, NULL, &sdata);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
}
// no sibling? can't merge
if (stag != LFSR_TAG_BRANCH) {
goto merge_abort;
}
d = lfsr_branch_fromdisk(lfs, &sibling, sdata);
if (d < 0) {
return d;
}
LFS_ASSERT(sibling.weight == sweight);
// try to add our sibling's tags to our rbyd
lfs_size_t rweight_ = rbyd_.weight;
id = 0;
tag = 0;
while (true) {
lfs_size_t w;
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, &sibling, id, lfsr_tag_next(tag),
&id, &tag, &w, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// append the attr
err = lfsr_rbyd_append(lfs, &rbyd_,
sdelta+id-lfs_smax32(w-1, 0), lfsr_tag_setmk(tag), +w,
data);
if (err) {
return err;
}
// if we exceed our compaction threshold our merge has
// failed, clean up ids and merge_abort
if (rbyd_.off > lfs->cfg->block_size/2) {
err = lfsr_rbyd_append(lfs, &rbyd_,
sdelta+(rbyd_.weight-rweight_)-1,
LFSR_TAG_MKUNR, -(rbyd_.weight-rweight_),
LFSR_DATA_NULL);
if (err) {
return err;
}
goto merge_abort;
}
}
if (sweight > 0 && rweight_ > 0) {
// bring in name that previously split the siblings
lfsr_tag_t split_tag;
lfsr_data_t split_data;
err = lfsr_rbyd_lookupnext(lfs, &parent,
(sdelta == 0 ? pid : sid), LFSR_TAG_NAME,
NULL, &split_tag, NULL, &split_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
if (lfsr_tag_suptype(split_tag) == LFSR_TAG_NAME) {
// lookup the id (weight really) of the previously-split entry
lfs_ssize_t split_id;
err = lfsr_rbyd_lookupnext(lfs, &rbyd_,
(sdelta == 0 ? sweight : rweight_), LFSR_TAG_NAME,
&split_id, NULL, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
err = lfsr_rbyd_append(lfs, &rbyd_,
split_id, LFSR_TAG_BNAME, 0, split_data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
}
err = lfsr_rbyd_commit(lfs, &rbyd_, NULL, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// we must have a parent at this point, but is our parent degenerate?
LFS_ASSERT(pid != -1);
if (pweight+sweight == lfsr_btree_weight(btree)) {
// collapse our parent, decreasing the height of the tree
*rbyd = rbyd_;
break;
} else {
// make pid the lower child so the following math is easier
if (pid > sid) {
lfs_sswap32(&pid, &sid);
lfs_swap32(&pweight, &sweight);
}
// cannibalize some attributes in our attr list to store
// our branch
uint8_t *scratch_buf = (uint8_t*)&attrs[3];
lfs_ssize_t d = lfsr_branch_todisk(lfs, &rbyd_, scratch_buf);
if (d < 0) {
return d;
}
// prepare commit to parent, tail recursing upwards
attrs[0] = LFSR_ATTR(sid, MKUNR, -sweight, NULL, 0);
attrs[1] = LFSR_ATTR(pid, UNR, +rbyd_.weight-pweight, NULL, 0);
attrs[2] = LFSR_ATTR(pid+rbyd_.weight-pweight, BRANCH, 0,
scratch_buf, d);
attr_count = 3;
}
*rbyd = parent;
cutoff = -1;
continue;
}
// at this point rbyd should be the trunk of our tree
btree->root = *rbyd;
return false;
}
static int lfsr_btree_push(lfs_t *lfs, lfsr_btree_t *btree,
lfs_size_t bid, lfsr_tag_t tag, lfs_size_t weight,
const void *buffer, lfs_size_t size) {
LFS_ASSERT(bid <= lfsr_btree_weight(btree));
// null btree?
if (lfsr_btree_isinlined(btree) && lfsr_btree_weight(btree) == 0) {
LFS_ASSERT(bid == 0);
btree->weight = lfsr_btree_setinlined(weight);
btree->inlined.tag = tag;
LFS_ASSERT(size <= LFSR_BTREE_INLINESIZE);
memcpy(btree->inlined.buffer, buffer, size);
btree->inlined.size = size;
return 0;
// inlined btree, need to expand into an rbyd
} else if (lfsr_btree_isinlined(btree)) {
lfsr_rbyd_t rbyd;
int err = lfsr_rbyd_alloc(lfs, &rbyd, 1);
if (err) {
return err;
}
// commit our entries
err = lfsr_rbyd_commit(lfs, &rbyd, LFSR_ATTRS(
LFSR_ATTR_(
0, lfsr_tag_setmk(btree->inlined.tag),
+lfsr_btree_weight(btree),
btree->inlined.buffer, btree->inlined.size),
LFSR_ATTR_(
bid, lfsr_tag_setmk(tag), +weight,
buffer, size)));
if (err) {
return err;
}
btree->root = rbyd;
return 0;
// a normal btree
} else {
// lookup in which leaf our id resides
//
// for lfsr_btree_commit operations to work out, we need to
// limit our bid to an id in the tree, which is what this min
// is doing
//
// note it is possible for our btree to have a weight of zero here,
// since we defer inlining until compaction time
lfs_size_t bid_ = lfs_min32(bid,
lfs_smax32(lfsr_btree_weight(btree)-1, 0));
lfsr_rbyd_t rbyd = btree->root;
lfs_ssize_t rid = -1;
lfs_size_t rweight = 0;
int err = lfsr_btree_lookupnext(lfs, btree, bid_,
NULL, &rbyd, &rid, NULL, &rweight, NULL,
false);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// adjust rid for push
if (bid >= lfsr_btree_weight(btree)) {
rid += 1;
} else {
rid -= rweight-1;
}
// commit our id into the tree, letting lfsr_btree_commit take care
// of the rest
int degenerate = lfsr_btree_commit(lfs, btree, bid_, 0, &rbyd,
LFSR_BTREE_ATTRS(
LFSR_ATTR_(rid, lfsr_tag_setmk(tag), +weight,
buffer, size)));
if (degenerate < 0) {
return degenerate;
}
// revert to an inlined btree
if (degenerate) {
btree->weight = lfsr_btree_setinlined(weight);
btree->inlined.tag = tag;
LFS_ASSERT(size <= LFSR_BTREE_INLINESIZE);
memcpy(btree->inlined.buffer, buffer, size);
btree->inlined.size = size;
}
return 0;
}
}
static int lfsr_btree_update(lfs_t *lfs, lfsr_btree_t *btree,
lfs_size_t bid, lfsr_tag_t tag, lfs_size_t weight,
const void *buffer, lfs_size_t size) {
LFS_ASSERT(bid < lfsr_btree_weight(btree));
LFS_ASSERT(lfsr_btree_weight(btree) > 0);
// inlined btree?
if (lfsr_btree_isinlined(btree)) {
LFS_ASSERT(bid == lfsr_btree_weight(btree)-1);
btree->weight = lfsr_btree_setinlined(weight);
btree->inlined.tag = tag;
LFS_ASSERT(size <= LFSR_BTREE_INLINESIZE);
memcpy(btree->inlined.buffer, buffer, size);
btree->inlined.size = size;
return 0;
// a normal btree
} else {
// lookup in which leaf our id resides
lfsr_rbyd_t rbyd;
lfsr_tag_t rtag;
lfs_ssize_t rid;
lfs_size_t rweight;
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, &rbyd, &rid, &rtag, &rweight, NULL,
false);
if (err) {
return err;
}
// commit our id into the tree, letting lfsr_btree_commit take care
// of the rest
int degenerate = lfsr_btree_commit(lfs, btree, bid, 1, &rbyd,
LFSR_BTREE_ATTRS(
(tag != rtag
? LFSR_ATTR_(rid, lfsr_tag_setrm(rtag), 0, NULL, 0)
: LFSR_ATTR_NOOP),
LFSR_ATTR_(rid, tag, 0, buffer, size),
LFSR_ATTR(rid, UNR, +weight-rweight, NULL, 0)));
if (degenerate < 0) {
return degenerate;
}
// revert to an inlined btree
if (degenerate) {
btree->weight = lfsr_btree_setinlined(weight);
btree->inlined.tag = tag;
LFS_ASSERT(size <= LFSR_BTREE_INLINESIZE);
memcpy(btree->inlined.buffer, buffer, size);
btree->inlined.size = size;
}
return 0;
}
}
static int lfsr_btree_pop(lfs_t *lfs, lfsr_btree_t *btree, lfs_size_t bid) {
LFS_ASSERT(bid < lfsr_btree_weight(btree));
LFS_ASSERT(lfsr_btree_weight(btree) > 0);
// inlined btree?
if (lfsr_btree_isinlined(btree)) {
LFS_ASSERT(bid == lfsr_btree_weight(btree)-1);
btree->weight = lfsr_btree_setinlined(0);
return 0;
// a normal btree
} else {
// lookup in which leaf our id resides
lfsr_rbyd_t rbyd;
lfsr_tag_t rtag;
lfs_ssize_t rid;
lfs_size_t rweight;
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, &rbyd, &rid, &rtag, &rweight, NULL,
false);
if (err) {
return err;
}
// remove our id, letting lfsr_btree_commit take care
// of the rest
//
// note we use a cutoff of 2 here, if we have 2 entries before
// the commit, we should have 1 entry after the commit and can
// revert to an inlined btree
int degenerate = lfsr_btree_commit(lfs, btree, bid, 2, &rbyd,
LFSR_BTREE_ATTRS(
LFSR_ATTR(rid, MKUNR, -rweight, NULL, 0)));
if (degenerate < 0) {
return degenerate;
}
// revert to a null btree
if (degenerate && rweight >= rbyd.weight) {
btree->weight = lfsr_btree_setinlined(0);
// revert to an inlined btree
} else if (degenerate) {
lfs_ssize_t sid;
// left sibling
if ((lfs_size_t)rid == rbyd.weight-1) {
sid = rid-rweight;
// right sibling
} else {
sid = rid+1;
}
lfsr_tag_t stag;
lfs_size_t sweight;
lfsr_data_t sdata;
int err = lfsr_rbyd_lookupnext(lfs, &rbyd, sid, LFSR_TAG_NAME,
&sid, &stag, &sweight, &sdata);
if (err) {
LFS_ASSERT(err == LFS_ERR_NOENT);
return err;
}
if (lfsr_tag_suptype(stag) == LFSR_TAG_NAME) {
err = lfsr_rbyd_lookupnext(lfs, &rbyd, sid, LFSR_TAG_STRUCT,
NULL, &stag, NULL, &sdata);
if (err) {
LFS_ASSERT(err == LFS_ERR_NOENT);
return err;
}
}
LFS_ASSERT(sweight+rweight == rbyd.weight);
btree->weight = lfsr_btree_setinlined(sweight);
btree->inlined.tag = stag;
LFS_ASSERT(lfsr_data_size(sdata) <= LFSR_BTREE_INLINESIZE);
err = lfsr_bd_read(lfs, sdata.disk.block, sdata.disk.off, 0,
btree->inlined.buffer, lfsr_data_size(sdata));
if (err) {
return err;
}
btree->inlined.size = lfsr_data_size(sdata);
}
return 0;
}
}
// lfsr_btree_split can be done with a update+push, but this function
// does all this in one commit, which is much more efficient
//
// this is also the only btree function that creates name entries, in theory
// push could as well, we just don't need the functionality for littlefs
//
static int lfsr_btree_split(lfs_t *lfs, lfsr_btree_t *btree,
lfs_size_t bid, const char *name, lfs_size_t name_size,
lfsr_tag_t tag1, lfs_size_t weight1,
const void *buffer1, lfs_size_t size1,
lfsr_tag_t tag2, lfs_size_t weight2,
const void *buffer2, lfs_size_t size2) {
LFS_ASSERT(bid < lfsr_btree_weight(btree));
LFS_ASSERT(lfsr_btree_weight(btree) > 0);
// inlined btree, need to expand into an rbyd
if (lfsr_btree_isinlined(btree)) {
lfsr_rbyd_t rbyd;
int err = lfsr_rbyd_alloc(lfs, &rbyd, 1);
if (err) {
return err;
}
// commit our entries
err = lfsr_rbyd_commit(lfs, &rbyd, LFSR_ATTRS(
LFSR_ATTR_(0, lfsr_tag_setmk(tag1), +weight1,
buffer1, size1),
(name_size > 0
? LFSR_ATTR(weight1, MKBNAME, +weight2,
name, name_size)
: LFSR_ATTR_NOOP),
(name_size > 0
? LFSR_ATTR_(weight1+weight2-1, tag2, 0,
buffer2, size2)
: LFSR_ATTR_(weight1, lfsr_tag_setmk(tag2), +weight2,
buffer2, size2))));
if (err) {
return err;
}
btree->root = rbyd;
return 0;
// a normal btree
} else {
// lookup in which leaf our bid resides
lfsr_rbyd_t rbyd;
lfs_ssize_t rid;
lfs_size_t rweight;
int err = lfsr_btree_lookupnext(lfs, btree, bid,
NULL, &rbyd, &rid, NULL, &rweight, NULL,
false);
if (err) {
return err;
}
// commit our bid into the tree, letting lfsr_btree_commit take care
// of the rest
int degenerate = lfsr_btree_commit(lfs, btree, bid, -1, &rbyd,
LFSR_BTREE_ATTRS(
LFSR_ATTR(rid, UNR, +weight1-rweight, NULL, 0),
LFSR_ATTR_(rid-(rweight-1)+weight1-1, tag1, 0,
buffer1, size1),
(name_size > 0
? LFSR_ATTR(rid-(rweight-1)+weight1, MKBNAME, +weight2,
name, name_size)
: LFSR_ATTR_NOOP),
(name_size > 0
? LFSR_ATTR_(rid-(rweight-1)+weight1+weight2-1, tag2, 0,
buffer2, size2)
: LFSR_ATTR_(rid-(rweight-1)+weight1,
lfsr_tag_setmk(tag2), +weight2,
buffer2, size2))));
if (degenerate < 0) {
return degenerate;
}
// this should never happen
LFS_ASSERT(!degenerate);
return 0;
}
}
/// Metadata pair operations ///
typedef struct lfsr_mpair {
lfs_block_t blocks[2];
} lfsr_mpair_t;
#define LFSR_MPAIR(block0, block1) ((lfsr_mpair_t){.blocks={block0, block1}})
static inline bool lfsr_mpair_eq(lfsr_mpair_t a, lfsr_mpair_t b) {
// allow either order
return (a.blocks[0] == b.blocks[0] && a.blocks[1] == b.blocks[1])
|| (a.blocks[0] == b.blocks[1] && a.blocks[1] == b.blocks[0]);
}
// 2 leb128 => 10 bytes (worst case)
#define LFSR_MPAIR_DSIZE (5+5)
static lfs_ssize_t lfsr_mpair_todisk(lfs_t *lfs, lfsr_mpair_t mpair,
uint8_t buffer[static LFSR_MPAIR_DSIZE]) {
(void)lfs;
lfs_ssize_t d = 0;
for (int i = 0; i < 2; i++) {
lfs_ssize_t d_ = lfs_toleb128(mpair.blocks[i], &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
}
return d;
}
// TODO should our fromdisk functions accept an lfsr_data_t?
static lfs_ssize_t lfsr_mpair_fromdisk(lfs_t *lfs, lfsr_mpair_t *mpair,
lfsr_data_t data) {
lfs_ssize_t d = 0;
for (int i = 0; i < 2; i++) {
lfs_ssize_t d_ = lfsr_data_readleb128(lfs, data, d, &mpair->blocks[i]);
if (d_ < 0) {
return d_;
}
d += d_;
}
return d;
}
static lfsr_mpair_t lfsr_mdir_mpair(const lfsr_mdir_t *mdir) {
return LFSR_MPAIR(mdir->rbyd.block, mdir->other_block);
}
static int lfsr_mdir_alloc(lfs_t *lfs, lfsr_mdir_t *mdir, lfs_ssize_t mid) {
// allocate two blocks
lfs_block_t blocks[2];
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &blocks[i]);
if (err) {
return err;
}
}
// rather than performing an unecessary erase, treat the current contents
// of the other block as a valid revision count
uint32_t rev;
int err = lfsr_bd_read(lfs, blocks[1], 0, 0, &rev, sizeof(uint32_t));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// note we can allow blocks that report corrupt here, with the assumption
// that all future reads will also return corrupt, this can happen if
// the underlying block device uses ECC that may be invalid when
// uninitialized
if (err == LFS_ERR_CORRUPT) {
rev = 0;
}
// TODO align to block_cycles
// setup mdir struct
mdir->mid = mid;
mdir->other_block = blocks[0];
mdir->rbyd.weight = 0;
mdir->rbyd.block = blocks[1];
// mark mdir as needing compaction
mdir->rbyd.off = lfs->cfg->block_size;
mdir->rbyd.trunk = 0;
mdir->rbyd.rev = rev;
return 0;
}
static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
lfs_ssize_t mid, lfsr_mpair_t mpair,
lfsr_find_t *find) {
// read both revision counts, try to figure out which block
// has the most recent revision
uint32_t revs[2] = {0, 0};
for (int i = 0; i < 2; i++) {
int err = lfsr_bd_read(lfs, mpair.blocks[0], 0, 0,
&revs[0], sizeof(uint32_t));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
revs[i] = lfs_fromle32_(&revs[i]);
if (i == 0
|| err == LFS_ERR_CORRUPT
|| lfs_scmp(revs[1], revs[0]) > 0) {
lfs_swap32(&mpair.blocks[0], &mpair.blocks[1]);
lfs_swap32(&revs[0], &revs[1]);
}
}
// try to fetch rbyds in the order of most recent to least recent
for (int i = 0; i < 2; i++) {
int err = lfsr_rbyd_fetch(lfs, &mdir->rbyd, mpair.blocks[0], 0, find);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (!err) {
mdir->mid = mid;
// keep track of other block for compactions
mdir->other_block = mpair.blocks[1];
return 0;
}
lfs_swap32(&mpair.blocks[0], &mpair.blocks[1]);
lfs_swap32(&revs[0], &revs[1]);
}
// could not find a non-corrupt rbyd
return LFS_ERR_CORRUPT;
}
static int lfsr_mdir_lookupnext(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfs_ssize_t id, lfsr_tag_t tag,
lfs_ssize_t *id_, lfsr_tag_t *tag_, lfs_size_t *weight_,
lfsr_data_t *data_) {
return lfsr_rbyd_lookupnext(lfs, &mdir->rbyd, id, tag,
id_, tag_, weight_, data_);
}
static int lfsr_mdir_lookup(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfs_ssize_t id, lfsr_tag_t tag,
lfsr_data_t *data_) {
return lfsr_rbyd_lookup(lfs, &mdir->rbyd, id, tag, data_);
}
// TODO do we need this?
// TODO move this into the tests?
static lfs_ssize_t lfsr_mdir_get(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfs_ssize_t id, lfsr_tag_t tag, void *buffer, lfs_size_t size) {
return lfsr_rbyd_get(lfs, &mdir->rbyd, id, tag, buffer, size);
}
// TODO how much of this code can we share with btree_commit?
// TODO share commit?
// TODO share split?
// TODO would be awfully convenient if c supported multiple returns
static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
const lfsr_attr_t *attrs, lfs_size_t attr_count) {
// TODO wait do we really need this loop?
while (true) {
// try to commit
int err = lfsr_rbyd_commit(lfs, &mdir->rbyd, attrs, attr_count);
if (err && err != LFS_ERR_RANGE) {
//TODO should we also move if there is corruption here?
return err;
}
// can't commit, try to compact
// TODO splits
// TODO relocations
lfsr_mdir_t mdir_;
bool issupermdirsplit = false; // TODO do this differently?
lfs_size_t lower_dsize = 0;
if (err) {
// normally the new mdir is just the flipped version of our
// current mdir
mdir_ = (lfsr_mdir_t){
.mid = mdir->mid,
.other_block = mdir->rbyd.block,
.rbyd.block = mdir->other_block,
// TODO rev things
.rbyd.rev = mdir->rbyd.rev + 1,
.rbyd.off = 0,
.rbyd.trunk = 0,
};
// TODO does this work with a chain of supermdirs?
// We do something a bit different here if we're the supermdir.
//
// Unlike btree splits, we can't resolve the transition to a
// non-inlined mtree with a single pcache. To work around this
// we estimate a worst-case size before compacting. This is more
// expensive in terms of reads, but avoids multiple erases.
if (lfsr_btree_isnull(&lfs->mtree)) {
// estimate the worst-case rbyd size
// TODO function for this?
lfs_size_t dsize = 4; // 4 bytes for rev
lfs_size_t dcount = 0;
lfs_ssize_t id = -1;
lfsr_tag_t tag = 0;
while (true) {
lfs_size_t w;
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
id, lfsr_tag_next(tag),
&id, &tag, &w, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// keep track of size and count of tags
dsize += LFSR_TAG_DSIZE + lfsr_data_size(data);
dcount += 1;
}
// TODO account for block_size limits in attr size dsizes?
// account for alt pointers
dsize += dcount*(LFSR_TAG_DSIZE * (2*lfs_nlog2(dcount)+1));
// keep rbyd < our compaction threshold (1/2) to avoid
// degenerate cases
if (dsize > lfs->cfg->block_size/2) {
// if we're an inlined mtree, convert to a normal tree
// _before_ splitting, this handles two cases nicely:
// 1. if our supermetadata takes up enough space we just
// need one child
// 2. if we need two children we need to separate the
// supermetadata out of the tree anyways
int err = lfsr_mdir_alloc(lfs, &mdir_, -2);
if (err) {
return err;
}
// TODO should mdir_alloc return something different?
// prepare for compact
mdir_.rbyd.off = 0;
issupermdirsplit = true;
}
}
int err = lfsr_bd_erase(lfs, mdir_.rbyd.block);
if (err) {
return err;
}
// try to copy over ids
//
// note we skip -1 ids if we're splitting our supermdir
lfs_ssize_t id = (issupermdirsplit ? 0 : -1);
lfsr_tag_t tag = 0;
while (true) {
lfs_size_t w;
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
id, lfsr_tag_next(tag),
&id, &tag, &w, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// keep track of worst-case encoding size in case we need to
// split
lower_dsize += LFSR_TAG_DSIZE + lfsr_data_size(data);
// append the attr
err = lfsr_rbyd_append(lfs, &mdir_.rbyd,
id-lfs_smax32(w-1, 0), lfsr_tag_setmk(tag), +w,
data);
if (err) {
return err;
}
// keep rbyd < our compaction threshold (1/2) to avoid
// degenerate cases
if (mdir_.rbyd.off > lfs->cfg->block_size/2) {
LFS_ASSERT(!lfsr_btree_isnull(&lfs->mtree)
|| issupermdirsplit);
goto split;
}
}
// commit pending attrs, taking care to split supermdir attrs
// from regular attrs if there is an mdir split or mtree update
//
// note we assume supermdir attrs are any -1 ids for now
for (lfs_size_t i = 0; i < attr_count; i++) {
if (!issupermdirsplit || attrs[i].id >= 0) {
err = lfsr_rbyd_append(lfs, &mdir_.rbyd,
attrs[i].id, attrs[i].tag, attrs[i].delta,
attrs[i].data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
}
// finalize commit
err = lfsr_rbyd_commit(lfs, &mdir_.rbyd, NULL, 0);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// update our mdir
//
// note we take care not to clobber the supermdir
// TODO ???
if (!(issupermdirsplit && mdir == &lfs->supermdir)) {
*mdir = mdir_;
}
if (issupermdirsplit) {
// update our mtree
uint8_t buf[LFSR_MPAIR_DSIZE];
lfs_ssize_t d = lfsr_mpair_todisk(lfs, lfsr_mdir_mpair(&mdir_),
buf);
if (d < 0) {
return d;
}
err = lfsr_btree_push(lfs, &lfs->mtree, 0, LFSR_TAG_MDIR, 1,
buf, d);
if (err) {
return err;
}
// we only reach this point if our supermdir is in need of
// compaction, so go ahead and compact
mdir_ = (lfsr_mdir_t){
.mid = -1,
.other_block = lfs->supermdir.rbyd.block,
.rbyd.block = lfs->supermdir.other_block,
// TODO rev things
.rbyd.rev = lfs->supermdir.rbyd.rev + 1,
.rbyd.off = 0,
.rbyd.trunk = 0,
};
int err = lfsr_bd_erase(lfs, mdir_.rbyd.block);
if (err) {
return err;
}
// try to copy over ids, since we split the supermdir
// we should only copy over supermdir attrs
//
// note we assume supermdir attrs are any -1 ids for now
lfs_ssize_t id = -1;
lfsr_tag_t tag = 0;
while (true) {
lfs_size_t w;
lfsr_data_t data;
err = lfsr_rbyd_lookupnext(lfs, &mdir->rbyd,
id, lfsr_tag_next(tag),
&id, &tag, &w, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT || id != -1) {
break;
}
// TODO we could clean this up if we don't deduplicate, but
// we should probably deduplicate all lfsr_rbyd_compact
// things
// append the attr
err = lfsr_rbyd_append(lfs, &mdir_.rbyd,
id-lfs_smax32(w-1, 0), lfsr_tag_setmk(tag), +w,
data);
if (err) {
return err;
}
// this must always fit our compaction threshold (1/2)
LFS_ASSERT(mdir_.rbyd.off > lfs->cfg->block_size/2);
}
// commit pending attrs, but only if they belong in the
// supermdir
for (lfs_size_t i = 0; i < attr_count; i++) {
if (attrs[i].id == -1) {
err = lfsr_rbyd_append(lfs, &mdir_.rbyd,
attrs[i].id, attrs[i].tag, attrs[i].delta,
attrs[i].data);
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
}
}
// finalize commit, and update the mtree
uint8_t buf_[LFSR_BTREE_DSIZE];
d = lfsr_btree_todisk(lfs, &lfs->mtree, &tag, buf_);
if (d < 0) {
return d;
}
err = lfsr_rbyd_commit(lfs, &mdir_.rbyd, LFSR_ATTRS(
// TODO yeah we're going to need a wide-rm
LFSR_ATTR(-1, RMMDIR, 0, NULL, 0),
LFSR_ATTR(-1, RMBRANCH, 0, NULL, 0),
LFSR_ATTR_(-1, tag, 0, buf_, d)));
if (err) {
LFS_ASSERT(err != LFS_ERR_RANGE);
return err;
}
// update the supermdir
lfs->supermdir = mdir_;
}
}
// done!
return 0;
split:;
LFS_ASSERT(false);
}
// done
return 0;
}
/// Superblock things ///
// These are all leb128s, but we can expect smaller encodings
// if we assume the version.
//
// - 7-bit major_version => 1 byte leb128 (worst case)
// - 7-bit minor_version => 1 byte leb128 (worst case)
// - 7-bit csum_type => 1 byte leb128 (worst case)
// - 7-bit flags => 1 byte leb128 (worst case)
// - 32-bit block_size => 5 byte leb128 (worst case)
// - 32-bit block_count => 5 byte leb128 (worst case)
// - 7-bit utag_limit => 1 byte leb128 (worst case)
// - 32-bit attr_limit => 5 byte leb128 (worst case)
// - 32-bit name_limit => 5 byte leb128 (worst case)
// - 32-bit file_limit => 5 byte leb128 (worst case)
// => 30 bytes total
//
#define LFSR_SUPERCONFIG_DSIZE (1+1+1+1+5+5+1+5+5+5)
static lfs_ssize_t lfsr_superconfig_todisk(lfs_t *lfs,
uint8_t buffer[static LFSR_SUPERCONFIG_DSIZE]) {
// TODO most of these should also be in the lfs_config/lfs_t structs
// note we take a shortcut for for single-byte leb128s, but these
// are still leb128s! the top bit must be zero!
// on-disk major version
buffer[0] = LFS_DISK_VERSION_MAJOR;
// on-disk minor version
buffer[1] = LFS_DISK_VERSION_MINOR;
// on-disk csum type
buffer[2] = 2;
// on-disk flags
buffer[3] = 0;
// on-disk block size
lfs_ssize_t d = 4;
lfs_ssize_t d_ = lfs_toleb128(lfs->cfg->block_size, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
// on-disk block count
d_ = lfs_toleb128(lfs->cfg->block_count, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
// on-disk utag limit
buffer[d] = 0x7f;
d += 1;
// on-disk attr limit
d_ = lfs_toleb128(0x7fffffff, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
// on-disk name limit
d_ = lfs_toleb128(0xff, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
// on-disk file limit
d_ = lfs_toleb128(0x7fffffff, &buffer[d], 5);
if (d_ < 0) {
return d_;
}
d += d_;
return d;
}
/// Filesystem init functions ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg);
static int lfs_deinit(lfs_t *lfs);
static int lfsr_mountinited(lfs_t *lfs) {
// scan for the first non-fake superblock
lfsr_mpair_t mpair = LFSR_MPAIR(0, 1);
lfsr_mdir_t mdir;
// detect cycles using Brent's algorithm
lfsr_mpair_t tortoise = LFSR_MPAIR(-1, -1);
lfs_size_t tortoise_i = 1;
lfs_size_t tortoise_period = 1;
while (true) {
// TODO detect cycles with Brent's algorithm
// found a cycle?
if (lfsr_mpair_eq(mpair, tortoise)) {
LFS_WARN("Cycle detected in superblocks");
return LFS_ERR_CORRUPT;
}
if (tortoise_i == tortoise_period) {
tortoise = mpair;
tortoise_i = 0;
tortoise_period *= 2;
}
tortoise_i += 1;
// fetch next possible superblock
int err = lfsr_mdir_fetch(lfs, &mdir, -1, mpair, NULL);
if (err) {
LFS_ERROR("No littlefs superblock found");
// treat corrupt errors as invalid littlefs images
if (err == LFS_ERR_CORRUPT) {
return LFS_ERR_INVAL;
}
return err;
}
// has magic string?
lfsr_data_t data;
err = lfsr_mdir_lookup(lfs, &mdir, -1, LFSR_TAG_SUPERMAGIC, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
int cmp;
err = lfsr_data_cmp(lfs, data, 0, "littlefs", 8, &cmp);
if (err) {
return err;
}
// treat corrupted magic as no magic
if (cmp != 0) {
err = LFS_ERR_NOENT;
}
}
if (err == LFS_ERR_NOENT) {
LFS_ERROR("No littlefs magic found");
return LFS_ERR_INVAL;
}
// lookup the superconfig
err = lfsr_mdir_lookup(lfs, &mdir, -1, LFSR_TAG_SUPERCONFIG, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT) {
// check the major/minor version
uint32_t major_version;
uint32_t minor_version;
lfs_size_t d = 0;
lfs_ssize_t d_ = lfsr_data_readleb128(lfs, data, d, &major_version);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
d_ = lfsr_data_readleb128(lfs, data, d, &minor_version);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
}
if (d_ == LFS_ERR_CORRUPT
|| major_version != LFS_DISK_VERSION_MAJOR
|| minor_version > LFS_DISK_VERSION_MINOR) {
LFS_ERROR("Incompatible version v%"PRIu32".%"PRIu32
" (!= v%"PRIu32".%"PRIu32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : major_version),
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : minor_version),
LFS_DISK_VERSION_MAJOR,
LFS_DISK_VERSION_MINOR);
return LFS_ERR_INVAL;
}
// check the on-disk csum type
uint32_t csum_type;
d_ = lfsr_data_readleb128(lfs, data, d, &csum_type);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || csum_type != 2) {
LFS_ERROR("Incompatible csum type 0x%"PRIx32
" (!= 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : csum_type),
2);
return LFS_ERR_INVAL;
}
// check for any on-disk flags
uint32_t flags;
d_ = lfsr_data_readleb128(lfs, data, d, &flags);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || flags != 0) {
LFS_ERROR("Incompatible flags 0x%"PRIx32
" (!= 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : flags),
0);
return LFS_ERR_INVAL;
}
// check the on-disk block size
// TODO actually use this
uint32_t block_size;
d_ = lfsr_data_readleb128(lfs, data, d, &block_size);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || block_size != lfs->cfg->block_size) {
LFS_ERROR("Incompatible block size 0x%"PRIx32
" (!= 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : block_size),
lfs->cfg->block_size);
return LFS_ERR_INVAL;
}
// check the on-disk block count
// TODO actually use this
uint32_t block_count;
d_ = lfsr_data_readleb128(lfs, data, d, &block_count);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || block_count != lfs->cfg->block_count) {
LFS_ERROR("Incompatible block count 0x%"PRIx32
" (!= 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : block_count),
lfs->cfg->block_count);
return LFS_ERR_INVAL;
}
// check the on-disk utag limit
// TODO actually use this
uint32_t utag_limit;
d_ = lfsr_data_readleb128(lfs, data, d, &utag_limit);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || utag_limit != 0x7f) {
LFS_ERROR("Incompatible utag limit 0x%"PRIx32
" (> 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : utag_limit),
0x7f);
return LFS_ERR_INVAL;
}
// check the on-disk attr limit
// TODO actually use this
uint32_t attr_limit;
d_ = lfsr_data_readleb128(lfs, data, d, &attr_limit);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || attr_limit != 0x7fffffff) {
LFS_ERROR("Incompatible attr limit 0x%"PRIx32
" (> 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : attr_limit),
0x7fffffff);
return LFS_ERR_INVAL;
}
// check the on-disk name limit
// TODO actually use this
uint32_t name_limit;
d_ = lfsr_data_readleb128(lfs, data, d, &name_limit);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || name_limit != 0xff) {
LFS_ERROR("Incompatible name limit 0x%"PRIx32
" (> 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : name_limit),
0xff);
return LFS_ERR_INVAL;
}
// check the on-disk file limit
// TODO actually use this
uint32_t file_limit;
d_ = lfsr_data_readleb128(lfs, data, d, &file_limit);
// treat any leb128 overflows as out-of-range values
if (d_ < 0 && d_ != LFS_ERR_CORRUPT) {
return d_;
}
if (d_ != LFS_ERR_CORRUPT) {
d += d_;
}
if (d_ == LFS_ERR_CORRUPT || file_limit != 0x7fffffff) {
LFS_ERROR("Incompatible file limit 0x%"PRIx32
" (> 0x%"PRIx32")",
(d_ == LFS_ERR_CORRUPT ? (uint32_t)-1 : file_limit),
0x7fffffff);
return LFS_ERR_INVAL;
}
}
// lookup supermdir
//
// if we have a supermdir, this is actually a fake superblock and
// we need to parse the next superblock in the chain
err = lfsr_mdir_lookup(lfs, &mdir, -1, LFSR_TAG_SUPERMDIR, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// no more supermdirs means we found our real superblock
if (err == LFS_ERR_NOENT) {
break;
}
lfs_ssize_t d = lfsr_mpair_fromdisk(lfs, &mpair, data);
if (d < 0) {
return d;
}
}
// do we have an mtree? this could be either a single mdir or a btree
// of mdirs
lfs_ssize_t id;
lfsr_tag_t tag;
lfsr_data_t data;
int err = lfsr_mdir_lookupnext(lfs, &mdir, -1, LFSR_TAG_STRUCT,
&id, &tag, NULL, &data);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT && id == -1) {
if (tag != LFSR_TAG_MDIR && tag != LFSR_TAG_BRANCH) {
LFS_ERROR("Weird superstruct? 0x%"PRIx32, tag);
return LFS_ERR_CORRUPT;
}
lfs_ssize_t d = lfsr_btree_fromdisk(lfs, &lfs->mtree, tag, 1, data);
if (d < 0) {
return d;
}
} else {
// TODO null?
lfs->mtree = LFSR_BTREE_NULL;
}
lfs->supermdir = mdir;
return 0;
}
static int lfsr_formatinited(lfs_t *lfs) {
uint8_t buf[LFSR_SUPERCONFIG_DSIZE];
lfs_ssize_t d = lfsr_superconfig_todisk(lfs, buf);
if (d < 0) {
return d;
}
for (int i = 0; i < 2; i++) {
// write superblock to both rbyds in the root supermdir to hopefully
// avoid mounting an older filesystem on disk
lfsr_rbyd_t rbyd = {.block=i, .rev=i+1, .off=0, .trunk=0};
int err = lfsr_bd_erase(lfs, rbyd.block);
if (err) {
return err;
}
err = lfsr_rbyd_commit(lfs, &rbyd, LFSR_ATTRS(
LFSR_ATTR(-1, SUPERMAGIC, 0, "littlefs", 8),
LFSR_ATTR(-1, SUPERCONFIG, 0, buf, d)));
if (err) {
return err;
}
}
// test that mount works with our formatted disk
int err = lfsr_mountinited(lfs);
if (err) {
return err;
}
return 0;
}
int lfsr_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// TODO this is a big hack to scaffold things until we have a working
// block allocator
//
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
lfs->free.off = 0;
lfs->free.size = lfs_min(8*lfs->cfg->lookahead_size,
lfs->cfg->block_count);
lfs->free.i = 2;
lfs_alloc_ack(lfs);
err = lfsr_mountinited(lfs);
if (err) {
// make sure we clean up on error
lfs_deinit(lfs);
return err;
}
return 0;
}
int lfsr_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
int lfsr_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// TODO this is a big hack to scaffold things until we have a working
// block allocator
//
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
lfs->free.off = 0;
lfs->free.size = lfs_min(8*lfs->cfg->lookahead_size,
lfs->cfg->block_count);
lfs->free.i = 2;
lfs_alloc_ack(lfs);
err = lfsr_formatinited(lfs);
if (err) {
// make sure we clean up on error
lfs_deinit(lfs);
return err;
}
return lfs_deinit(lfs);
}
/// Metadata pair and directory operations ///
static lfs_stag_t lfs_dir_getslice(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_tag_t gmask, lfs_tag_t gtag,
lfs_off_t goff, void *gbuffer, lfs_size_t gsize) {
lfs_off_t off = dir->off;
lfs_tag_t ntag = dir->etag;
lfs_stag_t gdiff = 0;
if (lfs_gstate_hasmovehere(&lfs->gdisk, dir->pair) &&
lfs_tag_id(gmask) != 0 &&
lfs_tag_id(lfs->gdisk.tag) <= lfs_tag_id(gtag)) {
// synthetic moves
gdiff -= LFS_MKTAG(0, 1, 0);
}
// iterate over dir block backwards (for faster lookups)
while (off >= sizeof(lfs_tag_t) + lfs_tag_dsize(ntag)) {
off -= lfs_tag_dsize(ntag);
lfs_tag_t tag = ntag;
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(ntag),
dir->pair[0], off, &ntag, sizeof(ntag));
if (err) {
return err;
}
ntag = (lfs_frombe32(ntag) ^ tag) & 0x7fffffff;
if (lfs_tag_id(gmask) != 0 &&
lfs_tag_type1(tag) == LFS_TYPE_SPLICE &&
lfs_tag_id(tag) <= lfs_tag_id(gtag - gdiff)) {
if (tag == (LFS_MKTAG(LFS_TYPE_CREATE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & (gtag - gdiff)))) {
// found where we were created
return LFS_ERR_NOENT;
}
// move around splices
gdiff += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
if ((gmask & tag) == (gmask & (gtag - gdiff))) {
if (lfs_tag_isdelete(tag)) {
return LFS_ERR_NOENT;
}
lfs_size_t diff = lfs_min(lfs_tag_size(tag), gsize);
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, diff,
dir->pair[0], off+sizeof(tag)+goff, gbuffer, diff);
if (err) {
return err;
}
memset((uint8_t*)gbuffer + diff, 0, gsize - diff);
return tag + gdiff;
}
}
return LFS_ERR_NOENT;
}
static lfs_stag_t lfs_dir_get(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_tag_t gmask, lfs_tag_t gtag, void *buffer) {
return lfs_dir_getslice(lfs, dir,
gmask, gtag,
0, buffer, lfs_tag_size(gtag));
}
static int lfs_dir_getread(lfs_t *lfs, const lfs_mdir_t *dir,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_tag_t gmask, lfs_tag_t gtag,
lfs_off_t off, void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT;
}
while (size > 0) {
lfs_size_t diff = size;
if (pcache && pcache->block == LFS_BLOCK_INLINE &&
off < pcache->off + pcache->size) {
if (off >= pcache->off) {
// is already in pcache?
diff = lfs_min(diff, pcache->size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// pcache takes priority
diff = lfs_min(diff, pcache->off-off);
}
if (rcache->block == LFS_BLOCK_INLINE &&
off < rcache->off + rcache->size) {
if (off >= rcache->off) {
// is already in rcache?
diff = lfs_min(diff, rcache->size - (off-rcache->off));
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// rcache takes priority
diff = lfs_min(diff, rcache->off-off);
}
// load to cache, first condition can no longer fail
rcache->block = LFS_BLOCK_INLINE;
rcache->off = lfs_aligndown(off, lfs->cfg->read_size);
rcache->size = lfs_min(lfs_alignup(off+hint, lfs->cfg->read_size),
lfs->cfg->cache_size);
int err = lfs_dir_getslice(lfs, dir, gmask, gtag,
rcache->off, rcache->buffer, rcache->size);
if (err < 0) {
return err;
}
}
return 0;
}
#ifndef LFS_READONLY
static int lfs_dir_traverse_filter(void *p,
lfs_tag_t tag, const void *buffer) {
lfs_tag_t *filtertag = p;
(void)buffer;
// which mask depends on unique bit in tag structure
uint32_t mask = (tag & LFS_MKTAG(0x100, 0, 0))
? LFS_MKTAG(0x7ff, 0x3ff, 0)
: LFS_MKTAG(0x700, 0x3ff, 0);
// check for redundancy
if ((mask & tag) == (mask & *filtertag) ||
lfs_tag_isdelete(*filtertag) ||
(LFS_MKTAG(0x7ff, 0x3ff, 0) & tag) == (
LFS_MKTAG(LFS_TYPE_DELETE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & *filtertag))) {
*filtertag = LFS_MKTAG(LFS_FROM_NOOP, 0, 0);
return true;
}
// check if we need to adjust for created/deleted tags
if (lfs_tag_type1(tag) == LFS_TYPE_SPLICE &&
lfs_tag_id(tag) <= lfs_tag_id(*filtertag)) {
*filtertag += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
return false;
}
#endif
#ifndef LFS_READONLY
// maximum recursive depth of lfs_dir_traverse, the deepest call:
//
// traverse with commit
// '-> traverse with move
// '-> traverse with filter
//
#define LFS_DIR_TRAVERSE_DEPTH 3
struct lfs_dir_traverse {
const lfs_mdir_t *dir;
lfs_off_t off;
lfs_tag_t ptag;
const struct lfs_mattr *attrs;
int attrcount;
lfs_tag_t tmask;
lfs_tag_t ttag;
uint16_t begin;
uint16_t end;
int16_t diff;
int (*cb)(void *data, lfs_tag_t tag, const void *buffer);
void *data;
lfs_tag_t tag;
const void *buffer;
struct lfs_diskoff disk;
};
static int lfs_dir_traverse(lfs_t *lfs,
const lfs_mdir_t *dir, lfs_off_t off, lfs_tag_t ptag,
const struct lfs_mattr *attrs, int attrcount,
lfs_tag_t tmask, lfs_tag_t ttag,
uint16_t begin, uint16_t end, int16_t diff,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
// This function in inherently recursive, but bounded. To allow tool-based
// analysis without unnecessary code-cost we use an explicit stack
struct lfs_dir_traverse stack[LFS_DIR_TRAVERSE_DEPTH-1];
unsigned sp = 0;
int res;
// iterate over directory and attrs
lfs_tag_t tag;
const void *buffer;
struct lfs_diskoff disk;
while (true) {
{
if (off+lfs_tag_dsize(ptag) < dir->off) {
off += lfs_tag_dsize(ptag);
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(tag),
dir->pair[0], off, &tag, sizeof(tag));
if (err) {
return err;
}
tag = (lfs_frombe32(tag) ^ ptag) | 0x80000000;
disk.block = dir->pair[0];
disk.off = off+sizeof(lfs_tag_t);
buffer = &disk;
ptag = tag;
} else if (attrcount > 0) {
tag = attrs[0].tag;
buffer = attrs[0].buffer;
attrs += 1;
attrcount -= 1;
} else {
// finished traversal, pop from stack?
res = 0;
break;
}
// do we need to filter?
lfs_tag_t mask = LFS_MKTAG(0x7ff, 0, 0);
if ((mask & tmask & tag) != (mask & tmask & ttag)) {
continue;
}
if (lfs_tag_id(tmask) != 0) {
LFS_ASSERT(sp < LFS_DIR_TRAVERSE_DEPTH);
// recurse, scan for duplicates, and update tag based on
// creates/deletes
stack[sp] = (struct lfs_dir_traverse){
.dir = dir,
.off = off,
.ptag = ptag,
.attrs = attrs,
.attrcount = attrcount,
.tmask = tmask,
.ttag = ttag,
.begin = begin,
.end = end,
.diff = diff,
.cb = cb,
.data = data,
.tag = tag,
.buffer = buffer,
.disk = disk,
};
sp += 1;
tmask = 0;
ttag = 0;
begin = 0;
end = 0;
diff = 0;
cb = lfs_dir_traverse_filter;
data = &stack[sp-1].tag;
continue;
}
}
popped:
// in filter range?
if (lfs_tag_id(tmask) != 0 &&
!(lfs_tag_id(tag) >= begin && lfs_tag_id(tag) < end)) {
continue;
}
// handle special cases for mcu-side operations
if (lfs_tag_type3(tag) == LFS_FROM_NOOP) {
// do nothing
} else if (lfs_tag_type3(tag) == LFS_FROM_MOVE) {
// Without this condition, lfs_dir_traverse can exhibit an
// extremely expensive O(n^3) of nested loops when renaming.
// This happens because lfs_dir_traverse tries to filter tags by
// the tags in the source directory, triggering a second
// lfs_dir_traverse with its own filter operation.
//
// traverse with commit
// '-> traverse with filter
// '-> traverse with move
// '-> traverse with filter
//
// However we don't actually care about filtering the second set of
// tags, since duplicate tags have no effect when filtering.
//
// This check skips this unnecessary recursive filtering explicitly,
// reducing this runtime from O(n^3) to O(n^2).
if (cb == lfs_dir_traverse_filter) {
continue;
}
// recurse into move
stack[sp] = (struct lfs_dir_traverse){
.dir = dir,
.off = off,
.ptag = ptag,
.attrs = attrs,
.attrcount = attrcount,
.tmask = tmask,
.ttag = ttag,
.begin = begin,
.end = end,
.diff = diff,
.cb = cb,
.data = data,
.tag = LFS_MKTAG(LFS_FROM_NOOP, 0, 0),
};
sp += 1;
uint16_t fromid = lfs_tag_size(tag);
uint16_t toid = lfs_tag_id(tag);
dir = buffer;
off = 0;
ptag = 0xffffffff;
attrs = NULL;
attrcount = 0;
tmask = LFS_MKTAG(0x600, 0x3ff, 0);
ttag = LFS_MKTAG(LFS_TYPE_STRUCT, 0, 0);
begin = fromid;
end = fromid+1;
diff = toid-fromid+diff;
} else if (lfs_tag_type3(tag) == LFS_FROM_USERATTRS) {
for (unsigned i = 0; i < lfs_tag_size(tag); i++) {
const struct lfs_attr *a = buffer;
res = cb(data, LFS_MKTAG(LFS_TYPE_USERATTR + a[i].type,
lfs_tag_id(tag) + diff, a[i].size), a[i].buffer);
if (res < 0) {
return res;
}
if (res) {
break;
}
}
} else {
res = cb(data, tag + LFS_MKTAG(0, diff, 0), buffer);
if (res < 0) {
return res;
}
if (res) {
break;
}
}
}
if (sp > 0) {
// pop from the stack and return, fortunately all pops share
// a destination
dir = stack[sp-1].dir;
off = stack[sp-1].off;
ptag = stack[sp-1].ptag;
attrs = stack[sp-1].attrs;
attrcount = stack[sp-1].attrcount;
tmask = stack[sp-1].tmask;
ttag = stack[sp-1].ttag;
begin = stack[sp-1].begin;
end = stack[sp-1].end;
diff = stack[sp-1].diff;
cb = stack[sp-1].cb;
data = stack[sp-1].data;
tag = stack[sp-1].tag;
buffer = stack[sp-1].buffer;
disk = stack[sp-1].disk;
sp -= 1;
goto popped;
} else {
return res;
}
}
#endif
static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2],
lfs_tag_t fmask, lfs_tag_t ftag, uint16_t *id,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
// we can find tag very efficiently during a fetch, since we're already
// scanning the entire directory
lfs_stag_t besttag = -1;
// if either block address is invalid we return LFS_ERR_CORRUPT here,
// otherwise later writes to the pair could fail
if (pair[0] >= lfs->cfg->block_count || pair[1] >= lfs->cfg->block_count) {
return LFS_ERR_CORRUPT;
}
// find the block with the most recent revision
uint32_t revs[2] = {0, 0};
int r = 0;
for (int i = 0; i < 2; i++) {
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(revs[i]),
pair[i], 0, &revs[i], sizeof(revs[i]));
revs[i] = lfs_fromle32(revs[i]);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err != LFS_ERR_CORRUPT &&
lfs_scmp(revs[i], revs[(i+1)%2]) > 0) {
r = i;
}
}
dir->pair[0] = pair[(r+0)%2];
dir->pair[1] = pair[(r+1)%2];
dir->rev = revs[(r+0)%2];
dir->off = 0; // nonzero = found some commits
// now scan tags to fetch the actual dir and find possible match
for (int i = 0; i < 2; i++) {
lfs_off_t off = 0;
lfs_tag_t ptag = 0xffffffff;
uint16_t tempcount = 0;
lfs_block_t temptail[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
bool tempsplit = false;
lfs_stag_t tempbesttag = besttag;
// assume not erased until proven otherwise
bool maybeerased = false;
bool hasfcrc = false;
struct lfs_fcrc fcrc;
dir->rev = lfs_tole32(dir->rev);
uint32_t crc = lfs_crc(0xffffffff, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
while (true) {
// extract next tag
lfs_tag_t tag;
off += lfs_tag_dsize(ptag);
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off, &tag, sizeof(tag));
if (err) {
if (err == LFS_ERR_CORRUPT) {
// can't continue?
break;
}
return err;
}
crc = lfs_crc(crc, &tag, sizeof(tag));
tag = lfs_frombe32(tag) ^ ptag;
// next commit not yet programmed?
if (!lfs_tag_isvalid(tag)) {
maybeerased = true;
break;
// out of range?
} else if (off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
break;
}
ptag = tag;
if (lfs_tag_type2(tag) == LFS_TYPE_CCRC) {
// check the crc attr
uint32_t dcrc;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag), &dcrc, sizeof(dcrc));
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
dcrc = lfs_fromle32(dcrc);
if (crc != dcrc) {
break;
}
// reset the next bit if we need to
ptag ^= (lfs_tag_t)(lfs_tag_chunk(tag) & 1U) << 31;
// toss our crc into the filesystem seed for
// pseudorandom numbers, note we use another crc here
// as a collection function because it is sufficiently
// random and convenient
lfs->seed = lfs_crc(lfs->seed, &crc, sizeof(crc));
// update with what's found so far
besttag = tempbesttag;
dir->off = off + lfs_tag_dsize(tag);
dir->etag = ptag;
dir->count = tempcount;
dir->tail[0] = temptail[0];
dir->tail[1] = temptail[1];
dir->split = tempsplit;
// reset crc
crc = 0xffffffff;
continue;
}
// fcrc is only valid when last tag was a crc
hasfcrc = false;
// crc the entry first, hopefully leaving it in the cache
err = lfs_bd_crc(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag),
lfs_tag_dsize(tag)-sizeof(tag), &crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
// directory modification tags?
if (lfs_tag_type1(tag) == LFS_TYPE_NAME) {
// increase count of files if necessary
if (lfs_tag_id(tag) >= tempcount) {
tempcount = lfs_tag_id(tag) + 1;
}
} else if (lfs_tag_type1(tag) == LFS_TYPE_SPLICE) {
tempcount += lfs_tag_splice(tag);
if (tag == (LFS_MKTAG(LFS_TYPE_DELETE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & tempbesttag))) {
tempbesttag |= 0x80000000;
} else if (tempbesttag != -1 &&
lfs_tag_id(tag) <= lfs_tag_id(tempbesttag)) {
tempbesttag += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
} else if (lfs_tag_type1(tag) == LFS_TYPE_TAIL) {
tempsplit = (lfs_tag_chunk(tag) & 1);
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag), &temptail, 8);
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
return err;
}
lfs_pair_fromle32(temptail);
} else if (lfs_tag_type3(tag) == LFS_TYPE_FCRC) {
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag),
&fcrc, sizeof(fcrc));
if (err) {
if (err == LFS_ERR_CORRUPT) {
break;
}
}
lfs_fcrc_fromle32(&fcrc);
hasfcrc = true;
}
// found a match for our fetcher?
if ((fmask & tag) == (fmask & ftag)) {
int res = cb(data, tag, &(struct lfs_diskoff){
dir->pair[0], off+sizeof(tag)});
if (res < 0) {
if (res == LFS_ERR_CORRUPT) {
break;
}
return res;
}
if (res == LFS_CMP_EQ) {
// found a match
tempbesttag = tag;
} else if ((LFS_MKTAG(0x7ff, 0x3ff, 0) & tag) ==
(LFS_MKTAG(0x7ff, 0x3ff, 0) & tempbesttag)) {
// found an identical tag, but contents didn't match
// this must mean that our besttag has been overwritten
tempbesttag = -1;
} else if (res == LFS_CMP_GT &&
lfs_tag_id(tag) <= lfs_tag_id(tempbesttag)) {
// found a greater match, keep track to keep things sorted
tempbesttag = tag | 0x80000000;
}
}
}
// found no valid commits?
if (dir->off == 0) {
// try the other block?
lfs_pair_swap(dir->pair);
dir->rev = revs[(r+1)%2];
continue;
}
// did we end on a valid commit? we may have an erased block
dir->erased = false;
if (maybeerased && hasfcrc && dir->off % lfs->cfg->prog_size == 0) {
// check for an fcrc matching the next prog's erased state, if
// this failed most likely a previous prog was interrupted, we
// need a new erase
uint32_t fcrc_ = 0xffffffff;
int err = lfs_bd_crc(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], dir->off, fcrc.size, &fcrc_);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// found beginning of erased part?
dir->erased = (fcrc_ == fcrc.crc);
}
// synthetic move
if (lfs_gstate_hasmovehere(&lfs->gdisk, dir->pair)) {
if (lfs_tag_id(lfs->gdisk.tag) == lfs_tag_id(besttag)) {
besttag |= 0x80000000;
} else if (besttag != -1 &&
lfs_tag_id(lfs->gdisk.tag) < lfs_tag_id(besttag)) {
besttag -= LFS_MKTAG(0, 1, 0);
}
}
// found tag? or found best id?
if (id) {
*id = lfs_min(lfs_tag_id(besttag), dir->count);
}
if (lfs_tag_isvalid(besttag)) {
return besttag;
} else if (lfs_tag_id(besttag) < dir->count) {
return LFS_ERR_NOENT;
} else {
return 0;
}
}
LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
dir->pair[0], dir->pair[1]);
return LFS_ERR_CORRUPT;
}
static int lfs_dir_fetch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2]) {
// note, mask=-1, tag=-1 can never match a tag since this
// pattern has the invalid bit set
return (int)lfs_dir_fetchmatch(lfs, dir, pair,
(lfs_tag_t)-1, (lfs_tag_t)-1, NULL, NULL, NULL);
}
static int lfs_dir_getgstate(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_gstate_t *gstate) {
lfs_gstate_t temp;
lfs_stag_t res = lfs_dir_get(lfs, dir, LFS_MKTAG(0x7ff, 0, 0),
LFS_MKTAG(LFS_TYPE_MOVESTATE, 0, sizeof(temp)), &temp);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
if (res != LFS_ERR_NOENT) {
// xor together to find resulting gstate
lfs_gstate_fromle32(&temp);
lfs_gstate_xor(gstate, &temp);
}
return 0;
}
static int lfs_dir_getinfo(lfs_t *lfs, lfs_mdir_t *dir,
uint16_t id, struct lfs_info *info) {
if (id == 0x3ff) {
// special case for root
strcpy(info->name, "/");
info->type = LFS_TYPE_DIR;
return 0;
}
lfs_stag_t tag = lfs_dir_get(lfs, dir, LFS_MKTAG(0x780, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_NAME, id, lfs->name_max+1), info->name);
if (tag < 0) {
return (int)tag;
}
info->type = lfs_tag_type3(tag);
struct lfs_ctz ctz;
tag = lfs_dir_get(lfs, dir, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, id, sizeof(ctz)), &ctz);
if (tag < 0) {
return (int)tag;
}
lfs_ctz_fromle32(&ctz);
if (lfs_tag_type3(tag) == LFS_TYPE_CTZSTRUCT) {
info->size = ctz.size;
} else if (lfs_tag_type3(tag) == LFS_TYPE_INLINESTRUCT) {
info->size = lfs_tag_size(tag);
}
return 0;
}
struct lfs_dir_find_match {
lfs_t *lfs;
const void *name;
lfs_size_t size;
};
static int lfs_dir_find_match(void *data,
lfs_tag_t tag, const void *buffer) {
struct lfs_dir_find_match *name = data;
lfs_t *lfs = name->lfs;
const struct lfs_diskoff *disk = buffer;
// compare with disk
lfs_size_t diff = lfs_min(name->size, lfs_tag_size(tag));
int res = lfs_bd_cmp(lfs,
NULL, &lfs->rcache, diff,
disk->block, disk->off, name->name, diff);
if (res != LFS_CMP_EQ) {
return res;
}
// only equal if our size is still the same
if (name->size != lfs_tag_size(tag)) {
return (name->size < lfs_tag_size(tag)) ? LFS_CMP_LT : LFS_CMP_GT;
}
// found a match!
return LFS_CMP_EQ;
}
static lfs_stag_t lfs_dir_find(lfs_t *lfs, lfs_mdir_t *dir,
const char **path, uint16_t *id) {
// we reduce path to a single name if we can find it
const char *name = *path;
if (id) {
*id = 0x3ff;
}
// default to root dir
lfs_stag_t tag = LFS_MKTAG(LFS_TYPE_DIR, 0x3ff, 0);
dir->tail[0] = lfs->root[0];
dir->tail[1] = lfs->root[1];
while (true) {
nextname:
// skip slashes
name += strspn(name, "/");
lfs_size_t namelen = strcspn(name, "/");
// skip '.' and root '..'
if ((namelen == 1 && memcmp(name, ".", 1) == 0) ||
(namelen == 2 && memcmp(name, "..", 2) == 0)) {
name += namelen;
goto nextname;
}
// skip if matched by '..' in name
const char *suffix = name + namelen;
lfs_size_t sufflen;
int depth = 1;
while (true) {
suffix += strspn(suffix, "/");
sufflen = strcspn(suffix, "/");
if (sufflen == 0) {
break;
}
if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
name = suffix + sufflen;
goto nextname;
}
} else {
depth += 1;
}
suffix += sufflen;
}
// found path
if (name[0] == '\0') {
return tag;
}
// update what we've found so far
*path = name;
// only continue if we hit a directory
if (lfs_tag_type3(tag) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
// grab the entry data
if (lfs_tag_id(tag) != 0x3ff) {
lfs_stag_t res = lfs_dir_get(lfs, dir, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), dir->tail);
if (res < 0) {
return res;
}
lfs_pair_fromle32(dir->tail);
}
// find entry matching name
while (true) {
tag = lfs_dir_fetchmatch(lfs, dir, dir->tail,
LFS_MKTAG(0x780, 0, 0),
LFS_MKTAG(LFS_TYPE_NAME, 0, namelen),
// are we last name?
(strchr(name, '/') == NULL) ? id : NULL,
lfs_dir_find_match, &(struct lfs_dir_find_match){
lfs, name, namelen});
if (tag < 0) {
return tag;
}
if (tag) {
break;
}
if (!dir->split) {
return LFS_ERR_NOENT;
}
}
// to next name
name += namelen;
}
}
// commit logic
struct lfs_commit {
lfs_block_t block;
lfs_off_t off;
lfs_tag_t ptag;
uint32_t crc;
lfs_off_t begin;
lfs_off_t end;
};
#ifndef LFS_READONLY
static int lfs_dir_commitprog(lfs_t *lfs, struct lfs_commit *commit,
const void *buffer, lfs_size_t size) {
int err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, false,
commit->block, commit->off ,
(const uint8_t*)buffer, size);
if (err) {
return err;
}
commit->crc = lfs_crc(commit->crc, buffer, size);
commit->off += size;
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_commitattr(lfs_t *lfs, struct lfs_commit *commit,
lfs_tag_t tag, const void *buffer) {
// check if we fit
lfs_size_t dsize = lfs_tag_dsize(tag);
if (commit->off + dsize > commit->end) {
return LFS_ERR_NOSPC;
}
// write out tag
lfs_tag_t ntag = lfs_tobe32((tag & 0x7fffffff) ^ commit->ptag);
int err = lfs_dir_commitprog(lfs, commit, &ntag, sizeof(ntag));
if (err) {
return err;
}
if (!(tag & 0x80000000)) {
// from memory
err = lfs_dir_commitprog(lfs, commit, buffer, dsize-sizeof(tag));
if (err) {
return err;
}
} else {
// from disk
const struct lfs_diskoff *disk = buffer;
for (lfs_off_t i = 0; i < dsize-sizeof(tag); i++) {
// rely on caching to make this efficient
uint8_t dat;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, dsize-sizeof(tag)-i,
disk->block, disk->off+i, &dat, 1);
if (err) {
return err;
}
err = lfs_dir_commitprog(lfs, commit, &dat, 1);
if (err) {
return err;
}
}
}
commit->ptag = tag & 0x7fffffff;
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
// align to program units
//
// this gets a bit complex as we have two types of crcs:
// - 5-word crc with fcrc to check following prog (middle of block)
// - 2-word crc with no following prog (end of block)
const lfs_off_t end = lfs_alignup(
lfs_min(commit->off + 5*sizeof(uint32_t), lfs->cfg->block_size),
lfs->cfg->prog_size);
lfs_off_t off1 = 0;
uint32_t crc1 = 0;
// create crc tags to fill up remainder of commit, note that
// padding is not crced, which lets fetches skip padding but
// makes committing a bit more complicated
while (commit->off < end) {
lfs_off_t noff = (
lfs_min(end - (commit->off+sizeof(lfs_tag_t)), 0x3fe)
+ (commit->off+sizeof(lfs_tag_t)));
// too large for crc tag? need padding commits
if (noff < end) {
noff = lfs_min(noff, end - 5*sizeof(uint32_t));
}
// space for fcrc?
uint8_t eperturb = -1;
if (noff >= end && noff <= lfs->cfg->block_size - lfs->cfg->prog_size) {
// first read the leading byte, this always contains a bit
// we can perturb to avoid writes that don't change the fcrc
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->prog_size,
commit->block, noff, &eperturb, 1);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// find the expected fcrc, don't bother avoiding a reread
// of the eperturb, it should still be in our cache
struct lfs_fcrc fcrc = {.size=lfs->cfg->prog_size, .crc=0xffffffff};
err = lfs_bd_crc(lfs,
NULL, &lfs->rcache, lfs->cfg->prog_size,
commit->block, noff, fcrc.size, &fcrc.crc);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
lfs_fcrc_tole32(&fcrc);
err = lfs_dir_commitattr(lfs, commit,
LFS_MKTAG(LFS_TYPE_FCRC, 0x3ff, sizeof(struct lfs_fcrc)),
&fcrc);
if (err) {
return err;
}
}
// build commit crc
struct {
lfs_tag_t tag;
uint32_t crc;
} ccrc;
lfs_tag_t ntag = LFS_MKTAG(
LFS_TYPE_CCRC + (((uint8_t)~eperturb) >> 7), 0x3ff,
noff - (commit->off+sizeof(lfs_tag_t)));
ccrc.tag = lfs_tobe32(ntag ^ commit->ptag);
commit->crc = lfs_crc(commit->crc, &ccrc.tag, sizeof(lfs_tag_t));
ccrc.crc = lfs_tole32(commit->crc);
int err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, false,
commit->block, commit->off, &ccrc, sizeof(ccrc));
if (err) {
return err;
}
// keep track of non-padding checksum to verify
if (off1 == 0) {
off1 = commit->off + sizeof(lfs_tag_t);
crc1 = commit->crc;
}
commit->off = noff;
// perturb valid bit?
commit->ptag = ntag ^ ((0x80 & ~eperturb) << 24);
// reset crc for next commit
commit->crc = 0xffffffff;
// manually flush here since we don't prog the padding, this confuses
// the caching layer
if (noff >= end || noff >= lfs->pcache.off + lfs->cfg->cache_size) {
// flush buffers
int err = lfs_bd_sync(lfs, &lfs->pcache, &lfs->rcache, false);
if (err) {
return err;
}
}
}
// successful commit, check checksums to make sure
//
// note that we don't need to check padding commits, worst
// case if they are corrupted we would have had to compact anyways
lfs_off_t off = commit->begin;
uint32_t crc = 0xffffffff;
int err = lfs_bd_crc(lfs,
NULL, &lfs->rcache, off1+sizeof(uint32_t),
commit->block, off, off1-off, &crc);
if (err) {
return err;
}
// check non-padding commits against known crc
if (crc != crc1) {
return LFS_ERR_CORRUPT;
}
// make sure to check crc in case we happen to pick
// up an unrelated crc (frozen block?)
err = lfs_bd_crc(lfs,
NULL, &lfs->rcache, sizeof(uint32_t),
commit->block, off1, sizeof(uint32_t), &crc);
if (err) {
return err;
}
if (crc != 0) {
return LFS_ERR_CORRUPT;
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_alloc(lfs_t *lfs, lfs_mdir_t *dir) {
// allocate pair of dir blocks (backwards, so we write block 1 first)
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &dir->pair[(i+1)%2]);
if (err) {
return err;
}
}
// zero for reproducibility in case initial block is unreadable
dir->rev = 0;
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(dir->rev),
dir->pair[0], 0, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// to make sure we don't immediately evict, align the new revision count
// to our block_cycles modulus, see lfs_dir_compact for why our modulus
// is tweaked this way
if (lfs->cfg->block_cycles > 0) {
dir->rev = lfs_alignup(dir->rev, ((lfs->cfg->block_cycles+1)|1));
}
// set defaults
dir->off = sizeof(dir->rev);
dir->etag = 0xffffffff;
dir->count = 0;
dir->tail[0] = LFS_BLOCK_NULL;
dir->tail[1] = LFS_BLOCK_NULL;
dir->erased = false;
dir->split = false;
// don't write out yet, let caller take care of that
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_drop(lfs_t *lfs, lfs_mdir_t *dir, lfs_mdir_t *tail) {
// steal state
int err = lfs_dir_getgstate(lfs, tail, &lfs->gdelta);
if (err) {
return err;
}
// steal tail
lfs_pair_tole32(tail->tail);
err = lfs_dir_commit(lfs, dir, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_TAIL + tail->split, 0x3ff, 8), tail->tail}));
lfs_pair_fromle32(tail->tail);
if (err) {
return err;
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_split(lfs_t *lfs,
lfs_mdir_t *dir, const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *source, uint16_t split, uint16_t end) {
// create tail metadata pair
lfs_mdir_t tail;
int err = lfs_dir_alloc(lfs, &tail);
if (err) {
return err;
}
tail.split = dir->split;
tail.tail[0] = dir->tail[0];
tail.tail[1] = dir->tail[1];
// note we don't care about LFS_OK_RELOCATED
int res = lfs_dir_compact(lfs, &tail, attrs, attrcount, source, split, end);
if (res < 0) {
return res;
}
dir->tail[0] = tail.pair[0];
dir->tail[1] = tail.pair[1];
dir->split = true;
// update root if needed
if (lfs_pair_cmp(dir->pair, lfs->root) == 0 && split == 0) {
lfs->root[0] = tail.pair[0];
lfs->root[1] = tail.pair[1];
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_commit_size(void *p, lfs_tag_t tag, const void *buffer) {
lfs_size_t *size = p;
(void)buffer;
*size += lfs_tag_dsize(tag);
return 0;
}
#endif
#ifndef LFS_READONLY
struct lfs_dir_commit_commit {
lfs_t *lfs;
struct lfs_commit *commit;
};
#endif
#ifndef LFS_READONLY
static int lfs_dir_commit_commit(void *p, lfs_tag_t tag, const void *buffer) {
struct lfs_dir_commit_commit *commit = p;
return lfs_dir_commitattr(commit->lfs, commit->commit, tag, buffer);
}
#endif
#ifndef LFS_READONLY
static bool lfs_dir_needsrelocation(lfs_t *lfs, lfs_mdir_t *dir) {
// If our revision count == n * block_cycles, we should force a relocation,
// this is how littlefs wear-levels at the metadata-pair level. Note that we
// actually use (block_cycles+1)|1, this is to avoid two corner cases:
// 1. block_cycles = 1, which would prevent relocations from terminating
// 2. block_cycles = 2n, which, due to aliasing, would only ever relocate
// one metadata block in the pair, effectively making this useless
return (lfs->cfg->block_cycles > 0
&& ((dir->rev + 1) % ((lfs->cfg->block_cycles+1)|1) == 0));
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_compact(lfs_t *lfs,
lfs_mdir_t *dir, const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *source, uint16_t begin, uint16_t end) {
// save some state in case block is bad
bool relocated = false;
bool tired = lfs_dir_needsrelocation(lfs, dir);
// increment revision count
dir->rev += 1;
// do not proactively relocate blocks during migrations, this
// can cause a number of failure states such: clobbering the
// v1 superblock if we relocate root, and invalidating directory
// pointers if we relocate the head of a directory. On top of
// this, relocations increase the overall complexity of
// lfs_migration, which is already a delicate operation.
#ifdef LFS_MIGRATE
if (lfs->lfs1) {
tired = false;
}
#endif
if (tired && lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) != 0) {
// we're writing too much, time to relocate
goto relocate;
}
// begin loop to commit compaction to blocks until a compact sticks
while (true) {
{
// setup commit state
struct lfs_commit commit = {
.block = dir->pair[1],
.off = 0,
.ptag = 0xffffffff,
.crc = 0xffffffff,
.begin = 0,
.end = (lfs->cfg->metadata_max ?
lfs->cfg->metadata_max : lfs->cfg->block_size) - 8,
};
// erase block to write to
int err = lfs_bd_erase(lfs, dir->pair[1]);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// write out header
dir->rev = lfs_tole32(dir->rev);
err = lfs_dir_commitprog(lfs, &commit,
&dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// traverse the directory, this time writing out all unique tags
err = lfs_dir_traverse(lfs,
source, 0, 0xffffffff, attrs, attrcount,
LFS_MKTAG(0x400, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
begin, end, -begin,
lfs_dir_commit_commit, &(struct lfs_dir_commit_commit){
lfs, &commit});
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// commit tail, which may be new after last size check
if (!lfs_pair_isnull(dir->tail)) {
lfs_pair_tole32(dir->tail);
err = lfs_dir_commitattr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_TAIL + dir->split, 0x3ff, 8),
dir->tail);
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
// bring over gstate?
lfs_gstate_t delta = {0};
if (!relocated) {
lfs_gstate_xor(&delta, &lfs->gdisk);
lfs_gstate_xor(&delta, &lfs->gstate);
}
lfs_gstate_xor(&delta, &lfs->gdelta);
delta.tag &= ~LFS_MKTAG(0, 0, 0x3ff);
err = lfs_dir_getgstate(lfs, dir, &delta);
if (err) {
return err;
}
if (!lfs_gstate_iszero(&delta)) {
lfs_gstate_tole32(&delta);
err = lfs_dir_commitattr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_MOVESTATE, 0x3ff,
sizeof(delta)), &delta);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
// complete commit with crc
err = lfs_dir_commitcrc(lfs, &commit);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// successful compaction, swap dir pair to indicate most recent
LFS_ASSERT(commit.off % lfs->cfg->prog_size == 0);
lfs_pair_swap(dir->pair);
dir->count = end - begin;
dir->off = commit.off;
dir->etag = commit.ptag;
// update gstate
lfs->gdelta = (lfs_gstate_t){0};
if (!relocated) {
lfs->gdisk = lfs->gstate;
}
}
break;
relocate:
// commit was corrupted, drop caches and prepare to relocate block
relocated = true;
lfs_cache_drop(lfs, &lfs->pcache);
if (!tired) {
LFS_DEBUG("Bad block at 0x%"PRIx32, dir->pair[1]);
}
// can't relocate superblock, filesystem is now frozen
if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
LFS_WARN("Superblock 0x%"PRIx32" has become unwritable",
dir->pair[1]);
return LFS_ERR_NOSPC;
}
// relocate half of pair
int err = lfs_alloc(lfs, &dir->pair[1]);
if (err && (err != LFS_ERR_NOSPC || !tired)) {
return err;
}
tired = false;
continue;
}
return relocated ? LFS_OK_RELOCATED : 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_splittingcompact(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *source, uint16_t begin, uint16_t end) {
while (true) {
// find size of first split, we do this by halving the split until
// the metadata is guaranteed to fit
//
// Note that this isn't a true binary search, we never increase the
// split size. This may result in poorly distributed metadata but isn't
// worth the extra code size or performance hit to fix.
lfs_size_t split = begin;
while (end - split > 1) {
lfs_size_t size = 0;
int err = lfs_dir_traverse(lfs,
source, 0, 0xffffffff, attrs, attrcount,
LFS_MKTAG(0x400, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
split, end, -split,
lfs_dir_commit_size, &size);
if (err) {
return err;
}
// space is complicated, we need room for:
//
// - tail: 4+2*4 = 12 bytes
// - gstate: 4+3*4 = 16 bytes
// - move delete: 4 = 4 bytes
// - crc: 4+4 = 8 bytes
// total = 40 bytes
//
// And we cap at half a block to avoid degenerate cases with
// nearly-full metadata blocks.
//
if (end - split < 0xff
&& size <= lfs_min(
lfs->cfg->block_size - 40,
lfs_alignup(
(lfs->cfg->metadata_max
? lfs->cfg->metadata_max
: lfs->cfg->block_size)/2,
lfs->cfg->prog_size))) {
break;
}
split = split + ((end - split) / 2);
}
if (split == begin) {
// no split needed
break;
}
// split into two metadata pairs and continue
int err = lfs_dir_split(lfs, dir, attrs, attrcount,
source, split, end);
if (err && err != LFS_ERR_NOSPC) {
return err;
}
if (err) {
// we can't allocate a new block, try to compact with degraded
// performance
LFS_WARN("Unable to split {0x%"PRIx32", 0x%"PRIx32"}",
dir->pair[0], dir->pair[1]);
break;
} else {
end = split;
}
}
if (lfs_dir_needsrelocation(lfs, dir)
&& lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0) {
// oh no! we're writing too much to the superblock,
// should we expand?
lfs_ssize_t size = lfs_fs_rawsize(lfs);
if (size < 0) {
return size;
}
// do we have extra space? littlefs can't reclaim this space
// by itself, so expand cautiously
if ((lfs_size_t)size < lfs->cfg->block_count/2) {
LFS_DEBUG("Expanding superblock at rev %"PRIu32, dir->rev);
int err = lfs_dir_split(lfs, dir, attrs, attrcount,
source, begin, end);
if (err && err != LFS_ERR_NOSPC) {
return err;
}
if (err) {
// welp, we tried, if we ran out of space there's not much
// we can do, we'll error later if we've become frozen
LFS_WARN("Unable to expand superblock");
} else {
end = begin;
}
}
}
return lfs_dir_compact(lfs, dir, attrs, attrcount, source, begin, end);
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_relocatingcommit(lfs_t *lfs, lfs_mdir_t *dir,
const lfs_block_t pair[2],
const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *pdir) {
int state = 0;
// calculate changes to the directory
bool hasdelete = false;
for (int i = 0; i < attrcount; i++) {
if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_CREATE) {
dir->count += 1;
} else if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(dir->count > 0);
dir->count -= 1;
hasdelete = true;
} else if (lfs_tag_type1(attrs[i].tag) == LFS_TYPE_TAIL) {
dir->tail[0] = ((lfs_block_t*)attrs[i].buffer)[0];
dir->tail[1] = ((lfs_block_t*)attrs[i].buffer)[1];
dir->split = (lfs_tag_chunk(attrs[i].tag) & 1);
lfs_pair_fromle32(dir->tail);
}
}
// should we actually drop the directory block?
if (hasdelete && dir->count == 0) {
LFS_ASSERT(pdir);
int err = lfs_fs_pred(lfs, dir->pair, pdir);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT && pdir->split) {
state = LFS_OK_DROPPED;
goto fixmlist;
}
}
if (dir->erased) {
// try to commit
struct lfs_commit commit = {
.block = dir->pair[0],
.off = dir->off,
.ptag = dir->etag,
.crc = 0xffffffff,
.begin = dir->off,
.end = (lfs->cfg->metadata_max ?
lfs->cfg->metadata_max : lfs->cfg->block_size) - 8,
};
// traverse attrs that need to be written out
lfs_pair_tole32(dir->tail);
int err = lfs_dir_traverse(lfs,
dir, dir->off, dir->etag, attrs, attrcount,
0, 0, 0, 0, 0,
lfs_dir_commit_commit, &(struct lfs_dir_commit_commit){
lfs, &commit});
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
// commit any global diffs if we have any
lfs_gstate_t delta = {0};
lfs_gstate_xor(&delta, &lfs->gstate);
lfs_gstate_xor(&delta, &lfs->gdisk);
lfs_gstate_xor(&delta, &lfs->gdelta);
delta.tag &= ~LFS_MKTAG(0, 0, 0x3ff);
if (!lfs_gstate_iszero(&delta)) {
err = lfs_dir_getgstate(lfs, dir, &delta);
if (err) {
return err;
}
lfs_gstate_tole32(&delta);
err = lfs_dir_commitattr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_MOVESTATE, 0x3ff,
sizeof(delta)), &delta);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
}
// finalize commit with the crc
err = lfs_dir_commitcrc(lfs, &commit);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
// successful commit, update dir
LFS_ASSERT(commit.off % lfs->cfg->prog_size == 0);
dir->off = commit.off;
dir->etag = commit.ptag;
// and update gstate
lfs->gdisk = lfs->gstate;
lfs->gdelta = (lfs_gstate_t){0};
goto fixmlist;
}
compact:
// fall back to compaction
lfs_cache_drop(lfs, &lfs->pcache);
state = lfs_dir_splittingcompact(lfs, dir, attrs, attrcount,
dir, 0, dir->count);
if (state < 0) {
return state;
}
goto fixmlist;
fixmlist:;
// this complicated bit of logic is for fixing up any active
// metadata-pairs that we may have affected
//
// note we have to make two passes since the mdir passed to
// lfs_dir_commit could also be in this list, and even then
// we need to copy the pair so they don't get clobbered if we refetch
// our mdir.
lfs_block_t oldpair[2] = {pair[0], pair[1]};
for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(d->m.pair, oldpair) == 0) {
d->m = *dir;
if (d->m.pair != pair) {
for (int i = 0; i < attrcount; i++) {
if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE &&
d->id == lfs_tag_id(attrs[i].tag)) {
d->m.pair[0] = LFS_BLOCK_NULL;
d->m.pair[1] = LFS_BLOCK_NULL;
} else if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_DELETE &&
d->id > lfs_tag_id(attrs[i].tag)) {
d->id -= 1;
if (d->type == LFS_TYPE_DIR) {
((lfs_dir_t*)d)->pos -= 1;
}
} else if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_CREATE &&
d->id >= lfs_tag_id(attrs[i].tag)) {
d->id += 1;
if (d->type == LFS_TYPE_DIR) {
((lfs_dir_t*)d)->pos += 1;
}
}
}
}
while (d->id >= d->m.count && d->m.split) {
// we split and id is on tail now
d->id -= d->m.count;
int err = lfs_dir_fetch(lfs, &d->m, d->m.tail);
if (err) {
return err;
}
}
}
}
return state;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_orphaningcommit(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs, int attrcount) {
// check for any inline files that aren't RAM backed and
// forcefully evict them, needed for filesystem consistency
for (lfs_file_t *f = (lfs_file_t*)lfs->mlist; f; f = f->next) {
if (dir != &f->m && lfs_pair_cmp(f->m.pair, dir->pair) == 0 &&
f->type == LFS_TYPE_REG && (f->flags & LFS_F_INLINE) &&
f->ctz.size > lfs->cfg->cache_size) {
int err = lfs_file_outline(lfs, f);
if (err) {
return err;
}
err = lfs_file_flush(lfs, f);
if (err) {
return err;
}
}
}
lfs_block_t lpair[2] = {dir->pair[0], dir->pair[1]};
lfs_mdir_t ldir = *dir;
lfs_mdir_t pdir;
int state = lfs_dir_relocatingcommit(lfs, &ldir, dir->pair,
attrs, attrcount, &pdir);
if (state < 0) {
return state;
}
// update if we're not in mlist, note we may have already been
// updated if we are in mlist
if (lfs_pair_cmp(dir->pair, lpair) == 0) {
*dir = ldir;
}
// commit was successful, but may require other changes in the
// filesystem, these would normally be tail recursive, but we have
// flattened them here avoid unbounded stack usage
// need to drop?
if (state == LFS_OK_DROPPED) {
// steal state
int err = lfs_dir_getgstate(lfs, dir, &lfs->gdelta);
if (err) {
return err;
}
// steal tail, note that this can't create a recursive drop
lpair[0] = pdir.pair[0];
lpair[1] = pdir.pair[1];
lfs_pair_tole32(dir->tail);
state = lfs_dir_relocatingcommit(lfs, &pdir, lpair, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_TAIL + dir->split, 0x3ff, 8),
dir->tail}),
NULL);
lfs_pair_fromle32(dir->tail);
if (state < 0) {
return state;
}
ldir = pdir;
}
// need to relocate?
bool orphans = false;
while (state == LFS_OK_RELOCATED) {
LFS_DEBUG("Relocating {0x%"PRIx32", 0x%"PRIx32"} "
"-> {0x%"PRIx32", 0x%"PRIx32"}",
lpair[0], lpair[1], ldir.pair[0], ldir.pair[1]);
state = 0;
// update internal root
if (lfs_pair_cmp(lpair, lfs->root) == 0) {
lfs->root[0] = ldir.pair[0];
lfs->root[1] = ldir.pair[1];
}
// update internally tracked dirs
for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(lpair, d->m.pair) == 0) {
d->m.pair[0] = ldir.pair[0];
d->m.pair[1] = ldir.pair[1];
}
if (d->type == LFS_TYPE_DIR &&
lfs_pair_cmp(lpair, ((lfs_dir_t*)d)->head) == 0) {
((lfs_dir_t*)d)->head[0] = ldir.pair[0];
((lfs_dir_t*)d)->head[1] = ldir.pair[1];
}
}
// find parent
lfs_stag_t tag = lfs_fs_parent(lfs, lpair, &pdir);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
bool hasparent = (tag != LFS_ERR_NOENT);
if (tag != LFS_ERR_NOENT) {
// note that if we have a parent, we must have a pred, so this will
// always create an orphan
int err = lfs_fs_preporphans(lfs, +1);
if (err) {
return err;
}
// fix pending move in this pair? this looks like an optimization but
// is in fact _required_ since relocating may outdate the move.
uint16_t moveid = 0x3ff;
if (lfs_gstate_hasmovehere(&lfs->gstate, pdir.pair)) {
moveid = lfs_tag_id(lfs->gstate.tag);
LFS_DEBUG("Fixing move while relocating "
"{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
pdir.pair[0], pdir.pair[1], moveid);
lfs_fs_prepmove(lfs, 0x3ff, NULL);
if (moveid < lfs_tag_id(tag)) {
tag -= LFS_MKTAG(0, 1, 0);
}
}
lfs_block_t ppair[2] = {pdir.pair[0], pdir.pair[1]};
lfs_pair_tole32(ldir.pair);
state = lfs_dir_relocatingcommit(lfs, &pdir, ppair, LFS_MKATTRS(
{LFS_MKTAG_IF(moveid != 0x3ff,
LFS_TYPE_DELETE, moveid, 0), NULL},
{tag, ldir.pair}),
NULL);
lfs_pair_fromle32(ldir.pair);
if (state < 0) {
return state;
}
if (state == LFS_OK_RELOCATED) {
lpair[0] = ppair[0];
lpair[1] = ppair[1];
ldir = pdir;
orphans = true;
continue;
}
}
// find pred
int err = lfs_fs_pred(lfs, lpair, &pdir);
if (err && err != LFS_ERR_NOENT) {
return err;
}
LFS_ASSERT(!(hasparent && err == LFS_ERR_NOENT));
// if we can't find dir, it must be new
if (err != LFS_ERR_NOENT) {
if (lfs_gstate_hasorphans(&lfs->gstate)) {
// next step, clean up orphans
err = lfs_fs_preporphans(lfs, -hasparent);
if (err) {
return err;
}
}
// fix pending move in this pair? this looks like an optimization
// but is in fact _required_ since relocating may outdate the move.
uint16_t moveid = 0x3ff;
if (lfs_gstate_hasmovehere(&lfs->gstate, pdir.pair)) {
moveid = lfs_tag_id(lfs->gstate.tag);
LFS_DEBUG("Fixing move while relocating "
"{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
pdir.pair[0], pdir.pair[1], moveid);
lfs_fs_prepmove(lfs, 0x3ff, NULL);
}
// replace bad pair, either we clean up desync, or no desync occured
lpair[0] = pdir.pair[0];
lpair[1] = pdir.pair[1];
lfs_pair_tole32(ldir.pair);
state = lfs_dir_relocatingcommit(lfs, &pdir, lpair, LFS_MKATTRS(
{LFS_MKTAG_IF(moveid != 0x3ff,
LFS_TYPE_DELETE, moveid, 0), NULL},
{LFS_MKTAG(LFS_TYPE_TAIL + pdir.split, 0x3ff, 8),
ldir.pair}),
NULL);
lfs_pair_fromle32(ldir.pair);
if (state < 0) {
return state;
}
ldir = pdir;
}
}
return orphans ? LFS_OK_ORPHANED : 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs, int attrcount) {
int orphans = lfs_dir_orphaningcommit(lfs, dir, attrs, attrcount);
if (orphans < 0) {
return orphans;
}
if (orphans) {
// make sure we've removed all orphans, this is a noop if there
// are none, but if we had nested blocks failures we may have
// created some
int err = lfs_fs_deorphan(lfs, false);
if (err) {
return err;
}
}
return 0;
}
#endif
/// Top level directory operations ///
#ifndef LFS_READONLY
static int lfs_rawmkdir(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
struct lfs_mlist cwd;
cwd.next = lfs->mlist;
uint16_t id;
err = lfs_dir_find(lfs, &cwd.m, &path, &id);
if (!(err == LFS_ERR_NOENT && id != 0x3ff)) {
return (err < 0) ? err : LFS_ERR_EXIST;
}
// check that name fits
lfs_size_t nlen = strlen(path);
if (nlen > lfs->name_max) {
return LFS_ERR_NAMETOOLONG;
}
// build up new directory
lfs_alloc_ack(lfs);
lfs_mdir_t dir;
err = lfs_dir_alloc(lfs, &dir);
if (err) {
return err;
}
// find end of list
lfs_mdir_t pred = cwd.m;
while (pred.split) {
err = lfs_dir_fetch(lfs, &pred, pred.tail);
if (err) {
return err;
}
}
// setup dir
lfs_pair_tole32(pred.tail);
err = lfs_dir_commit(lfs, &dir, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 8), pred.tail}));
lfs_pair_fromle32(pred.tail);
if (err) {
return err;
}
// current block not end of list?
if (cwd.m.split) {
// update tails, this creates a desync
err = lfs_fs_preporphans(lfs, +1);
if (err) {
return err;
}
// it's possible our predecessor has to be relocated, and if
// our parent is our predecessor's predecessor, this could have
// caused our parent to go out of date, fortunately we can hook
// ourselves into littlefs to catch this
cwd.type = 0;
cwd.id = 0;
lfs->mlist = &cwd;
lfs_pair_tole32(dir.pair);
err = lfs_dir_commit(lfs, &pred, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 8), dir.pair}));
lfs_pair_fromle32(dir.pair);
if (err) {
lfs->mlist = cwd.next;
return err;
}
lfs->mlist = cwd.next;
err = lfs_fs_preporphans(lfs, -1);
if (err) {
return err;
}
}
// now insert into our parent block
lfs_pair_tole32(dir.pair);
err = lfs_dir_commit(lfs, &cwd.m, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_CREATE, id, 0), NULL},
{LFS_MKTAG(LFS_TYPE_DIR, id, nlen), path},
{LFS_MKTAG(LFS_TYPE_DIRSTRUCT, id, 8), dir.pair},
{LFS_MKTAG_IF(!cwd.m.split,
LFS_TYPE_SOFTTAIL, 0x3ff, 8), dir.pair}));
lfs_pair_fromle32(dir.pair);
if (err) {
return err;
}
return 0;
}
#endif
static int lfs_dir_rawopen(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
lfs_stag_t tag = lfs_dir_find(lfs, &dir->m, &path, NULL);
if (tag < 0) {
return tag;
}
if (lfs_tag_type3(tag) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
lfs_block_t pair[2];
if (lfs_tag_id(tag) == 0x3ff) {
// handle root dir separately
pair[0] = lfs->root[0];
pair[1] = lfs->root[1];
} else {
// get dir pair from parent
lfs_stag_t res = lfs_dir_get(lfs, &dir->m, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
}
// fetch first pair
int err = lfs_dir_fetch(lfs, &dir->m, pair);
if (err) {
return err;
}
// setup entry
dir->head[0] = dir->m.pair[0];
dir->head[1] = dir->m.pair[1];
dir->id = 0;
dir->pos = 0;
// add to list of mdirs
dir->type = LFS_TYPE_DIR;
lfs_mlist_append(lfs, (struct lfs_mlist *)dir);
return 0;
}
static int lfs_dir_rawclose(lfs_t *lfs, lfs_dir_t *dir) {
// remove from list of mdirs
lfs_mlist_remove(lfs, (struct lfs_mlist *)dir);
return 0;
}
static int lfs_dir_rawread(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info) {
memset(info, 0, sizeof(*info));
// special offset for '.' and '..'
if (dir->pos == 0) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, ".");
dir->pos += 1;
return true;
} else if (dir->pos == 1) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, "..");
dir->pos += 1;
return true;
}
while (true) {
if (dir->id == dir->m.count) {
if (!dir->m.split) {
return false;
}
int err = lfs_dir_fetch(lfs, &dir->m, dir->m.tail);
if (err) {
return err;
}
dir->id = 0;
}
int err = lfs_dir_getinfo(lfs, &dir->m, dir->id, info);
if (err && err != LFS_ERR_NOENT) {
return err;
}
dir->id += 1;
if (err != LFS_ERR_NOENT) {
break;
}
}
dir->pos += 1;
return true;
}
static int lfs_dir_rawseek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
// simply walk from head dir
int err = lfs_dir_rawrewind(lfs, dir);
if (err) {
return err;
}
// first two for ./..
dir->pos = lfs_min(2, off);
off -= dir->pos;
// skip superblock entry
dir->id = (off > 0 && lfs_pair_cmp(dir->head, lfs->root) == 0);
while (off > 0) {
int diff = lfs_min(dir->m.count - dir->id, off);
dir->id += diff;
dir->pos += diff;
off -= diff;
if (dir->id == dir->m.count) {
if (!dir->m.split) {
return LFS_ERR_INVAL;
}
err = lfs_dir_fetch(lfs, &dir->m, dir->m.tail);
if (err) {
return err;
}
dir->id = 0;
}
}
return 0;
}
static lfs_soff_t lfs_dir_rawtell(lfs_t *lfs, lfs_dir_t *dir) {
(void)lfs;
return dir->pos;
}
static int lfs_dir_rawrewind(lfs_t *lfs, lfs_dir_t *dir) {
// reload the head dir
int err = lfs_dir_fetch(lfs, &dir->m, dir->head);
if (err) {
return err;
}
dir->id = 0;
dir->pos = 0;
return 0;
}
/// File index list operations ///
static int lfs_ctz_index(lfs_t *lfs, lfs_off_t *off) {
lfs_off_t size = *off;
lfs_off_t b = lfs->cfg->block_size - 2*4;
lfs_off_t i = size / b;
if (i == 0) {
return 0;
}
i = (size - 4*(lfs_popc(i-1)+2)) / b;
*off = size - b*i - 4*lfs_popc(i);
return i;
}
static int lfs_ctz_find(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
if (size == 0) {
*block = LFS_BLOCK_NULL;
*off = 0;
return 0;
}
lfs_off_t current = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
lfs_off_t target = lfs_ctz_index(lfs, &pos);
while (current > target) {
lfs_size_t skip = lfs_min(
lfs_npw2(current-target+1) - 1,
lfs_ctz(current));
int err = lfs_bd_read(lfs,
pcache, rcache, sizeof(head),
head, 4*skip, &head, sizeof(head));
head = lfs_fromle32(head);
if (err) {
return err;
}
current -= 1 << skip;
}
*block = head;
*off = pos;
return 0;
}
#ifndef LFS_READONLY
static int lfs_ctz_extend(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
lfs_block_t *block, lfs_off_t *off) {
while (true) {
// go ahead and grab a block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
{
err = lfs_bd_erase(lfs, nblock);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (size == 0) {
*block = nblock;
*off = 0;
return 0;
}
lfs_size_t noff = size - 1;
lfs_off_t index = lfs_ctz_index(lfs, &noff);
noff = noff + 1;
// just copy out the last block if it is incomplete
if (noff != lfs->cfg->block_size) {
for (lfs_off_t i = 0; i < noff; i++) {
uint8_t data;
err = lfs_bd_read(lfs,
NULL, rcache, noff-i,
head, i, &data, 1);
if (err) {
return err;
}
err = lfs_bd_prog(lfs,
pcache, rcache, true,
nblock, i, &data, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
*block = nblock;
*off = noff;
return 0;
}
// append block
index += 1;
lfs_size_t skips = lfs_ctz(index) + 1;
lfs_block_t nhead = head;
for (lfs_off_t i = 0; i < skips; i++) {
nhead = lfs_tole32(nhead);
err = lfs_bd_prog(lfs, pcache, rcache, true,
nblock, 4*i, &nhead, 4);
nhead = lfs_fromle32(nhead);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (i != skips-1) {
err = lfs_bd_read(lfs,
NULL, rcache, sizeof(nhead),
nhead, 4*i, &nhead, sizeof(nhead));
nhead = lfs_fromle32(nhead);
if (err) {
return err;
}
}
}
*block = nblock;
*off = 4*skips;
return 0;
}
relocate:
LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);
// just clear cache and try a new block
lfs_cache_drop(lfs, pcache);
}
}
#endif
static int lfs_ctz_traverse(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
int (*cb)(void*, lfs_block_t), void *data) {
if (size == 0) {
return 0;
}
lfs_off_t index = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
while (true) {
int err = cb(data, head);
if (err) {
return err;
}
if (index == 0) {
return 0;
}
lfs_block_t heads[2];
int count = 2 - (index & 1);
err = lfs_bd_read(lfs,
pcache, rcache, count*sizeof(head),
head, 0, &heads, count*sizeof(head));
heads[0] = lfs_fromle32(heads[0]);
heads[1] = lfs_fromle32(heads[1]);
if (err) {
return err;
}
for (int i = 0; i < count-1; i++) {
err = cb(data, heads[i]);
if (err) {
return err;
}
}
head = heads[count-1];
index -= count;
}
}
/// Top level file operations ///
static int lfs_file_rawopencfg(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags,
const struct lfs_file_config *cfg) {
#ifndef LFS_READONLY
// deorphan if we haven't yet, needed at most once after poweron
if ((flags & LFS_O_WRONLY) == LFS_O_WRONLY) {
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
}
#else
LFS_ASSERT((flags & LFS_O_RDONLY) == LFS_O_RDONLY);
#endif
// setup simple file details
int err;
file->cfg = cfg;
file->flags = flags;
file->pos = 0;
file->off = 0;
file->cache.buffer = NULL;
// allocate entry for file if it doesn't exist
lfs_stag_t tag = lfs_dir_find(lfs, &file->m, &path, &file->id);
if (tag < 0 && !(tag == LFS_ERR_NOENT && file->id != 0x3ff)) {
err = tag;
goto cleanup;
}
// get id, add to list of mdirs to catch update changes
file->type = LFS_TYPE_REG;
lfs_mlist_append(lfs, (struct lfs_mlist *)file);
#ifdef LFS_READONLY
if (tag == LFS_ERR_NOENT) {
err = LFS_ERR_NOENT;
goto cleanup;
#else
if (tag == LFS_ERR_NOENT) {
if (!(flags & LFS_O_CREAT)) {
err = LFS_ERR_NOENT;
goto cleanup;
}
// check that name fits
lfs_size_t nlen = strlen(path);
if (nlen > lfs->name_max) {
err = LFS_ERR_NAMETOOLONG;
goto cleanup;
}
// get next slot and create entry to remember name
err = lfs_dir_commit(lfs, &file->m, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_CREATE, file->id, 0), NULL},
{LFS_MKTAG(LFS_TYPE_REG, file->id, nlen), path},
{LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0), NULL}));
// it may happen that the file name doesn't fit in the metadata blocks, e.g., a 256 byte file name will
// not fit in a 128 byte block.
err = (err == LFS_ERR_NOSPC) ? LFS_ERR_NAMETOOLONG : err;
if (err) {
goto cleanup;
}
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, 0);
} else if (flags & LFS_O_EXCL) {
err = LFS_ERR_EXIST;
goto cleanup;
#endif
} else if (lfs_tag_type3(tag) != LFS_TYPE_REG) {
err = LFS_ERR_ISDIR;
goto cleanup;
#ifndef LFS_READONLY
} else if (flags & LFS_O_TRUNC) {
// truncate if requested
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0);
file->flags |= LFS_F_DIRTY;
#endif
} else {
// try to load what's on disk, if it's inlined we'll fix it later
tag = lfs_dir_get(lfs, &file->m, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, file->id, 8), &file->ctz);
if (tag < 0) {
err = tag;
goto cleanup;
}
lfs_ctz_fromle32(&file->ctz);
}
// fetch attrs
for (unsigned i = 0; i < file->cfg->attr_count; i++) {
// if opened for read / read-write operations
if ((file->flags & LFS_O_RDONLY) == LFS_O_RDONLY) {
lfs_stag_t res = lfs_dir_get(lfs, &file->m,
LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_USERATTR + file->cfg->attrs[i].type,
file->id, file->cfg->attrs[i].size),
file->cfg->attrs[i].buffer);
if (res < 0 && res != LFS_ERR_NOENT) {
err = res;
goto cleanup;
}
}
#ifndef LFS_READONLY
// if opened for write / read-write operations
if ((file->flags & LFS_O_WRONLY) == LFS_O_WRONLY) {
if (file->cfg->attrs[i].size > lfs->attr_max) {
err = LFS_ERR_NOSPC;
goto cleanup;
}
file->flags |= LFS_F_DIRTY;
}
#endif
}
// allocate buffer if needed
if (file->cfg->buffer) {
file->cache.buffer = file->cfg->buffer;
} else {
file->cache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!file->cache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// zero to avoid information leak
lfs_cache_zero(lfs, &file->cache);
if (lfs_tag_type3(tag) == LFS_TYPE_INLINESTRUCT) {
// load inline files
file->ctz.head = LFS_BLOCK_INLINE;
file->ctz.size = lfs_tag_size(tag);
file->flags |= LFS_F_INLINE;
file->cache.block = file->ctz.head;
file->cache.off = 0;
file->cache.size = lfs->cfg->cache_size;
// don't always read (may be new/trunc file)
if (file->ctz.size > 0) {
lfs_stag_t res = lfs_dir_get(lfs, &file->m,
LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, file->id,
lfs_min(file->cache.size, 0x3fe)),
file->cache.buffer);
if (res < 0) {
err = res;
goto cleanup;
}
}
}
return 0;
cleanup:
// clean up lingering resources
#ifndef LFS_READONLY
file->flags |= LFS_F_ERRED;
#endif
lfs_file_rawclose(lfs, file);
return err;
}
#ifndef LFS_NO_MALLOC
static int lfs_file_rawopen(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags) {
static const struct lfs_file_config defaults = {0};
int err = lfs_file_rawopencfg(lfs, file, path, flags, &defaults);
return err;
}
#endif
static int lfs_file_rawclose(lfs_t *lfs, lfs_file_t *file) {
#ifndef LFS_READONLY
int err = lfs_file_rawsync(lfs, file);
#else
int err = 0;
#endif
// remove from list of mdirs
lfs_mlist_remove(lfs, (struct lfs_mlist*)file);
// clean up memory
if (!file->cfg->buffer) {
lfs_free(file->cache.buffer);
}
return err;
}
#ifndef LFS_READONLY
static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
while (true) {
// just relocate what exists into new block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
err = lfs_bd_erase(lfs, nblock);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// either read from dirty cache or disk
for (lfs_off_t i = 0; i < file->off; i++) {
uint8_t data;
if (file->flags & LFS_F_INLINE) {
err = lfs_dir_getread(lfs, &file->m,
// note we evict inline files before they can be dirty
NULL, &file->cache, file->off-i,
LFS_MKTAG(0xfff, 0x1ff, 0),
LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0),
i, &data, 1);
if (err) {
return err;
}
} else {
err = lfs_bd_read(lfs,
&file->cache, &lfs->rcache, file->off-i,
file->block, i, &data, 1);
if (err) {
return err;
}
}
err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, true,
nblock, i, &data, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
// copy over new state of file
memcpy(file->cache.buffer, lfs->pcache.buffer, lfs->cfg->cache_size);
file->cache.block = lfs->pcache.block;
file->cache.off = lfs->pcache.off;
file->cache.size = lfs->pcache.size;
lfs_cache_zero(lfs, &lfs->pcache);
file->block = nblock;
file->flags |= LFS_F_WRITING;
return 0;
relocate:
LFS_DEBUG("Bad block at 0x%"PRIx32, nblock);
// just clear cache and try a new block
lfs_cache_drop(lfs, &lfs->pcache);
}
}
#endif
#ifndef LFS_READONLY
static int lfs_file_outline(lfs_t *lfs, lfs_file_t *file) {
file->off = file->pos;
lfs_alloc_ack(lfs);
int err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
file->flags &= ~LFS_F_INLINE;
return 0;
}
#endif
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
if (file->flags & LFS_F_READING) {
if (!(file->flags & LFS_F_INLINE)) {
lfs_cache_drop(lfs, &file->cache);
}
file->flags &= ~LFS_F_READING;
}
#ifndef LFS_READONLY
if (file->flags & LFS_F_WRITING) {
lfs_off_t pos = file->pos;
if (!(file->flags & LFS_F_INLINE)) {
// copy over anything after current branch
lfs_file_t orig = {
.ctz.head = file->ctz.head,
.ctz.size = file->ctz.size,
.flags = LFS_O_RDONLY,
.pos = file->pos,
.cache = lfs->rcache,
};
lfs_cache_drop(lfs, &lfs->rcache);
while (file->pos < file->ctz.size) {
// copy over a byte at a time, leave it up to caching
// to make this efficient
uint8_t data;
lfs_ssize_t res = lfs_file_flushedread(lfs, &orig, &data, 1);
if (res < 0) {
return res;
}
res = lfs_file_flushedwrite(lfs, file, &data, 1);
if (res < 0) {
return res;
}
// keep our reference to the rcache in sync
if (lfs->rcache.block != LFS_BLOCK_NULL) {
lfs_cache_drop(lfs, &orig.cache);
lfs_cache_drop(lfs, &lfs->rcache);
}
}
// write out what we have
while (true) {
int err = lfs_bd_flush(lfs, &file->cache, &lfs->rcache, true);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
break;
relocate:
LFS_DEBUG("Bad block at 0x%"PRIx32, file->block);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
}
} else {
file->pos = lfs_max(file->pos, file->ctz.size);
}
// actual file updates
file->ctz.head = file->block;
file->ctz.size = file->pos;
file->flags &= ~LFS_F_WRITING;
file->flags |= LFS_F_DIRTY;
file->pos = pos;
}
#endif
return 0;
}
#ifndef LFS_READONLY
static int lfs_file_rawsync(lfs_t *lfs, lfs_file_t *file) {
if (file->flags & LFS_F_ERRED) {
// it's not safe to do anything if our file errored
return 0;
}
int err = lfs_file_flush(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
if ((file->flags & LFS_F_DIRTY) &&
!lfs_pair_isnull(file->m.pair)) {
// update dir entry
uint16_t type;
const void *buffer;
lfs_size_t size;
struct lfs_ctz ctz;
if (file->flags & LFS_F_INLINE) {
// inline the whole file
type = LFS_TYPE_INLINESTRUCT;
buffer = file->cache.buffer;
size = file->ctz.size;
} else {
// update the ctz reference
type = LFS_TYPE_CTZSTRUCT;
// copy ctz so alloc will work during a relocate
ctz = file->ctz;
lfs_ctz_tole32(&ctz);
buffer = &ctz;
size = sizeof(ctz);
}
// commit file data and attributes
err = lfs_dir_commit(lfs, &file->m, LFS_MKATTRS(
{LFS_MKTAG(type, file->id, size), buffer},
{LFS_MKTAG(LFS_FROM_USERATTRS, file->id,
file->cfg->attr_count), file->cfg->attrs}));
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
file->flags &= ~LFS_F_DIRTY;
}
return 0;
}
#endif
static lfs_ssize_t lfs_file_flushedread(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
lfs_size_t nsize = size;
if (file->pos >= file->ctz.size) {
// eof if past end
return 0;
}
size = lfs_min(size, file->ctz.size - file->pos);
nsize = size;
while (nsize > 0) {
// check if we need a new block
if (!(file->flags & LFS_F_READING) ||
file->off == lfs->cfg->block_size) {
if (!(file->flags & LFS_F_INLINE)) {
int err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
file->pos, &file->block, &file->off);
if (err) {
return err;
}
} else {
file->block = LFS_BLOCK_INLINE;
file->off = file->pos;
}
file->flags |= LFS_F_READING;
}
// read as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
if (file->flags & LFS_F_INLINE) {
int err = lfs_dir_getread(lfs, &file->m,
NULL, &file->cache, lfs->cfg->block_size,
LFS_MKTAG(0xfff, 0x1ff, 0),
LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0),
file->off, data, diff);
if (err) {
return err;
}
} else {
int err = lfs_bd_read(lfs,
NULL, &file->cache, lfs->cfg->block_size,
file->block, file->off, data, diff);
if (err) {
return err;
}
}
file->pos += diff;
file->off += diff;
data += diff;
nsize -= diff;
}
return size;
}
static lfs_ssize_t lfs_file_rawread(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
LFS_ASSERT((file->flags & LFS_O_RDONLY) == LFS_O_RDONLY);
#ifndef LFS_READONLY
if (file->flags & LFS_F_WRITING) {
// flush out any writes
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
#endif
return lfs_file_flushedread(lfs, file, buffer, size);
}
#ifndef LFS_READONLY
static lfs_ssize_t lfs_file_flushedwrite(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & LFS_F_INLINE) &&
lfs_max(file->pos+nsize, file->ctz.size) >
lfs_min(0x3fe, lfs_min(
lfs->cfg->cache_size,
(lfs->cfg->metadata_max ?
lfs->cfg->metadata_max : lfs->cfg->block_size) / 8))) {
// inline file doesn't fit anymore
int err = lfs_file_outline(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
}
while (nsize > 0) {
// check if we need a new block
if (!(file->flags & LFS_F_WRITING) ||
file->off == lfs->cfg->block_size) {
if (!(file->flags & LFS_F_INLINE)) {
if (!(file->flags & LFS_F_WRITING) && file->pos > 0) {
// find out which block we're extending from
int err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
file->pos-1, &file->block, &file->off);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
// mark cache as dirty since we may have read data into it
lfs_cache_zero(lfs, &file->cache);
}
// extend file with new blocks
lfs_alloc_ack(lfs);
int err = lfs_ctz_extend(lfs, &file->cache, &lfs->rcache,
file->block, file->pos,
&file->block, &file->off);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
} else {
file->block = LFS_BLOCK_INLINE;
file->off = file->pos;
}
file->flags |= LFS_F_WRITING;
}
// program as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
while (true) {
int err = lfs_bd_prog(lfs, &file->cache, &lfs->rcache, true,
file->block, file->off, data, diff);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
file->flags |= LFS_F_ERRED;
return err;
}
break;
relocate:
err = lfs_file_relocate(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
}
file->pos += diff;
file->off += diff;
data += diff;
nsize -= diff;
lfs_alloc_ack(lfs);
}
return size;
}
static lfs_ssize_t lfs_file_rawwrite(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
LFS_ASSERT((file->flags & LFS_O_WRONLY) == LFS_O_WRONLY);
if (file->flags & LFS_F_READING) {
// drop any reads
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if ((file->flags & LFS_O_APPEND) && file->pos < file->ctz.size) {
file->pos = file->ctz.size;
}
if (file->pos + size > lfs->file_max) {
// Larger than file limit?
return LFS_ERR_FBIG;
}
if (!(file->flags & LFS_F_WRITING) && file->pos > file->ctz.size) {
// fill with zeros
lfs_off_t pos = file->pos;
file->pos = file->ctz.size;
while (file->pos < pos) {
lfs_ssize_t res = lfs_file_flushedwrite(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
}
lfs_ssize_t nsize = lfs_file_flushedwrite(lfs, file, buffer, size);
if (nsize < 0) {
return nsize;
}
file->flags &= ~LFS_F_ERRED;
return nsize;
}
#endif
static lfs_soff_t lfs_file_rawseek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
// find new pos
lfs_off_t npos = file->pos;
if (whence == LFS_SEEK_SET) {
npos = off;
} else if (whence == LFS_SEEK_CUR) {
if ((lfs_soff_t)file->pos + off < 0) {
return LFS_ERR_INVAL;
} else {
npos = file->pos + off;
}
} else if (whence == LFS_SEEK_END) {
lfs_soff_t res = lfs_file_rawsize(lfs, file) + off;
if (res < 0) {
return LFS_ERR_INVAL;
} else {
npos = res;
}
}
if (npos > lfs->file_max) {
// file position out of range
return LFS_ERR_INVAL;
}
if (file->pos == npos) {
// noop - position has not changed
return npos;
}
// if we're only reading and our new offset is still in the file's cache
// we can avoid flushing and needing to reread the data
if (
#ifndef LFS_READONLY
!(file->flags & LFS_F_WRITING)
#else
true
#endif
) {
int oindex = lfs_ctz_index(lfs, &(lfs_off_t){file->pos});
lfs_off_t noff = npos;
int nindex = lfs_ctz_index(lfs, &noff);
if (oindex == nindex
&& noff >= file->cache.off
&& noff < file->cache.off + file->cache.size) {
file->pos = npos;
file->off = noff;
return npos;
}
}
// write out everything beforehand, may be noop if rdonly
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// update pos
file->pos = npos;
return npos;
}
#ifndef LFS_READONLY
static int lfs_file_rawtruncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
LFS_ASSERT((file->flags & LFS_O_WRONLY) == LFS_O_WRONLY);
if (size > LFS_FILE_MAX) {
return LFS_ERR_INVAL;
}
lfs_off_t pos = file->pos;
lfs_off_t oldsize = lfs_file_rawsize(lfs, file);
if (size < oldsize) {
// need to flush since directly changing metadata
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// lookup new head in ctz skip list
err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
size, &file->block, &file->off);
if (err) {
return err;
}
// need to set pos/block/off consistently so seeking back to
// the old position does not get confused
file->pos = size;
file->ctz.head = file->block;
file->ctz.size = size;
file->flags |= LFS_F_DIRTY | LFS_F_READING;
} else if (size > oldsize) {
// flush+seek if not already at end
lfs_soff_t res = lfs_file_rawseek(lfs, file, 0, LFS_SEEK_END);
if (res < 0) {
return (int)res;
}
// fill with zeros
while (file->pos < size) {
res = lfs_file_rawwrite(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return (int)res;
}
}
}
// restore pos
lfs_soff_t res = lfs_file_rawseek(lfs, file, pos, LFS_SEEK_SET);
if (res < 0) {
return (int)res;
}
return 0;
}
#endif
static lfs_soff_t lfs_file_rawtell(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
return file->pos;
}
static int lfs_file_rawrewind(lfs_t *lfs, lfs_file_t *file) {
lfs_soff_t res = lfs_file_rawseek(lfs, file, 0, LFS_SEEK_SET);
if (res < 0) {
return (int)res;
}
return 0;
}
static lfs_soff_t lfs_file_rawsize(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
#ifndef LFS_READONLY
if (file->flags & LFS_F_WRITING) {
return lfs_max(file->pos, file->ctz.size);
}
#endif
return file->ctz.size;
}
/// General fs operations ///
static int lfs_rawstat(lfs_t *lfs, const char *path, struct lfs_info *info) {
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0) {
return (int)tag;
}
return lfs_dir_getinfo(lfs, &cwd, lfs_tag_id(tag), info);
}
#ifndef LFS_READONLY
static int lfs_rawremove(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0 || lfs_tag_id(tag) == 0x3ff) {
return (tag < 0) ? (int)tag : LFS_ERR_INVAL;
}
struct lfs_mlist dir;
dir.next = lfs->mlist;
if (lfs_tag_type3(tag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t pair[2];
lfs_stag_t res = lfs_dir_get(lfs, &cwd, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return (int)res;
}
lfs_pair_fromle32(pair);
err = lfs_dir_fetch(lfs, &dir.m, pair);
if (err) {
return err;
}
if (dir.m.count > 0 || dir.m.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
err = lfs_fs_preporphans(lfs, +1);
if (err) {
return err;
}
// I know it's crazy but yes, dir can be changed by our parent's
// commit (if predecessor is child)
dir.type = 0;
dir.id = 0;
lfs->mlist = &dir;
}
// delete the entry
err = lfs_dir_commit(lfs, &cwd, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(tag), 0), NULL}));
if (err) {
lfs->mlist = dir.next;
return err;
}
lfs->mlist = dir.next;
if (lfs_tag_type3(tag) == LFS_TYPE_DIR) {
// fix orphan
err = lfs_fs_preporphans(lfs, -1);
if (err) {
return err;
}
err = lfs_fs_pred(lfs, dir.m.pair, &cwd);
if (err) {
return err;
}
err = lfs_dir_drop(lfs, &cwd, &dir.m);
if (err) {
return err;
}
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_rawrename(lfs_t *lfs, const char *oldpath, const char *newpath) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
// find old entry
lfs_mdir_t oldcwd;
lfs_stag_t oldtag = lfs_dir_find(lfs, &oldcwd, &oldpath, NULL);
if (oldtag < 0 || lfs_tag_id(oldtag) == 0x3ff) {
return (oldtag < 0) ? (int)oldtag : LFS_ERR_INVAL;
}
// find new entry
lfs_mdir_t newcwd;
uint16_t newid;
lfs_stag_t prevtag = lfs_dir_find(lfs, &newcwd, &newpath, &newid);
if ((prevtag < 0 || lfs_tag_id(prevtag) == 0x3ff) &&
!(prevtag == LFS_ERR_NOENT && newid != 0x3ff)) {
return (prevtag < 0) ? (int)prevtag : LFS_ERR_INVAL;
}
// if we're in the same pair there's a few special cases...
bool samepair = (lfs_pair_cmp(oldcwd.pair, newcwd.pair) == 0);
uint16_t newoldid = lfs_tag_id(oldtag);
struct lfs_mlist prevdir;
prevdir.next = lfs->mlist;
if (prevtag == LFS_ERR_NOENT) {
// check that name fits
lfs_size_t nlen = strlen(newpath);
if (nlen > lfs->name_max) {
return LFS_ERR_NAMETOOLONG;
}
// there is a small chance we are being renamed in the same
// directory/ to an id less than our old id, the global update
// to handle this is a bit messy
if (samepair && newid <= newoldid) {
newoldid += 1;
}
} else if (lfs_tag_type3(prevtag) != lfs_tag_type3(oldtag)) {
return LFS_ERR_ISDIR;
} else if (samepair && newid == newoldid) {
// we're renaming to ourselves??
return 0;
} else if (lfs_tag_type3(prevtag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t prevpair[2];
lfs_stag_t res = lfs_dir_get(lfs, &newcwd, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, newid, 8), prevpair);
if (res < 0) {
return (int)res;
}
lfs_pair_fromle32(prevpair);
// must be empty before removal
err = lfs_dir_fetch(lfs, &prevdir.m, prevpair);
if (err) {
return err;
}
if (prevdir.m.count > 0 || prevdir.m.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
err = lfs_fs_preporphans(lfs, +1);
if (err) {
return err;
}
// I know it's crazy but yes, dir can be changed by our parent's
// commit (if predecessor is child)
prevdir.type = 0;
prevdir.id = 0;
lfs->mlist = &prevdir;
}
if (!samepair) {
lfs_fs_prepmove(lfs, newoldid, oldcwd.pair);
}
// move over all attributes
err = lfs_dir_commit(lfs, &newcwd, LFS_MKATTRS(
{LFS_MKTAG_IF(prevtag != LFS_ERR_NOENT,
LFS_TYPE_DELETE, newid, 0), NULL},
{LFS_MKTAG(LFS_TYPE_CREATE, newid, 0), NULL},
{LFS_MKTAG(lfs_tag_type3(oldtag), newid, strlen(newpath)), newpath},
{LFS_MKTAG(LFS_FROM_MOVE, newid, lfs_tag_id(oldtag)), &oldcwd},
{LFS_MKTAG_IF(samepair,
LFS_TYPE_DELETE, newoldid, 0), NULL}));
if (err) {
lfs->mlist = prevdir.next;
return err;
}
// let commit clean up after move (if we're different! otherwise move
// logic already fixed it for us)
if (!samepair && lfs_gstate_hasmove(&lfs->gstate)) {
// prep gstate and delete move id
lfs_fs_prepmove(lfs, 0x3ff, NULL);
err = lfs_dir_commit(lfs, &oldcwd, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_DELETE, lfs_tag_id(oldtag), 0), NULL}));
if (err) {
lfs->mlist = prevdir.next;
return err;
}
}
lfs->mlist = prevdir.next;
if (prevtag != LFS_ERR_NOENT
&& lfs_tag_type3(prevtag) == LFS_TYPE_DIR) {
// fix orphan
err = lfs_fs_preporphans(lfs, -1);
if (err) {
return err;
}
err = lfs_fs_pred(lfs, prevdir.m.pair, &newcwd);
if (err) {
return err;
}
err = lfs_dir_drop(lfs, &newcwd, &prevdir.m);
if (err) {
return err;
}
}
return 0;
}
#endif
static lfs_ssize_t lfs_rawgetattr(lfs_t *lfs, const char *path,
uint8_t type, void *buffer, lfs_size_t size) {
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0) {
return tag;
}
uint16_t id = lfs_tag_id(tag);
if (id == 0x3ff) {
// special case for root
id = 0;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
}
tag = lfs_dir_get(lfs, &cwd, LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_USERATTR + type,
id, lfs_min(size, lfs->attr_max)),
buffer);
if (tag < 0) {
if (tag == LFS_ERR_NOENT) {
return LFS_ERR_NOATTR;
}
return tag;
}
return lfs_tag_size(tag);
}
#ifndef LFS_READONLY
static int lfs_commitattr(lfs_t *lfs, const char *path,
uint8_t type, const void *buffer, lfs_size_t size) {
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0) {
return tag;
}
uint16_t id = lfs_tag_id(tag);
if (id == 0x3ff) {
// special case for root
id = 0;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
}
return lfs_dir_commit(lfs, &cwd, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_USERATTR + type, id, size), buffer}));
}
#endif
#ifndef LFS_READONLY
static int lfs_rawsetattr(lfs_t *lfs, const char *path,
uint8_t type, const void *buffer, lfs_size_t size) {
if (size > lfs->attr_max) {
return LFS_ERR_NOSPC;
}
return lfs_commitattr(lfs, path, type, buffer, size);
}
#endif
#ifndef LFS_READONLY
static int lfs_rawremoveattr(lfs_t *lfs, const char *path, uint8_t type) {
return lfs_commitattr(lfs, path, type, NULL, 0x3ff);
}
#endif
/// Filesystem operations ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
lfs->cfg = cfg;
int err = 0;
// validate that the lfs-cfg sizes were initiated properly before
// performing any arithmetic logics with them
LFS_ASSERT(lfs->cfg->read_size != 0);
LFS_ASSERT(lfs->cfg->prog_size != 0);
LFS_ASSERT(lfs->cfg->cache_size != 0);
// check that block size is a multiple of cache size is a multiple
// of prog and read sizes
LFS_ASSERT(lfs->cfg->cache_size % lfs->cfg->read_size == 0);
LFS_ASSERT(lfs->cfg->cache_size % lfs->cfg->prog_size == 0);
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->cache_size == 0);
// check that the block size is large enough to fit ctz pointers
LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
<= lfs->cfg->block_size);
// block_cycles = 0 is no longer supported.
//
// block_cycles is the number of erase cycles before littlefs evicts
// metadata logs as a part of wear leveling. Suggested values are in the
// range of 100-1000, or set block_cycles to -1 to disable block-level
// wear-leveling.
LFS_ASSERT(lfs->cfg->block_cycles != 0);
// setup read cache
if (lfs->cfg->read_buffer) {
lfs->rcache.buffer = lfs->cfg->read_buffer;
} else {
lfs->rcache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!lfs->rcache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// setup program cache
if (lfs->cfg->prog_buffer) {
lfs->pcache.buffer = lfs->cfg->prog_buffer;
} else {
lfs->pcache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!lfs->pcache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// zero to avoid information leaks
lfs_cache_zero(lfs, &lfs->rcache);
lfs_cache_zero(lfs, &lfs->pcache);
// setup lookahead, must be multiple of 64-bits, 32-bit aligned
LFS_ASSERT(lfs->cfg->lookahead_size > 0);
LFS_ASSERT(lfs->cfg->lookahead_size % 8 == 0 &&
(uintptr_t)lfs->cfg->lookahead_buffer % 4 == 0);
if (lfs->cfg->lookahead_buffer) {
lfs->free.buffer = lfs->cfg->lookahead_buffer;
} else {
lfs->free.buffer = lfs_malloc(lfs->cfg->lookahead_size);
if (!lfs->free.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// check that the size limits are sane
LFS_ASSERT(lfs->cfg->name_max <= LFS_NAME_MAX);
lfs->name_max = lfs->cfg->name_max;
if (!lfs->name_max) {
lfs->name_max = LFS_NAME_MAX;
}
LFS_ASSERT(lfs->cfg->file_max <= LFS_FILE_MAX);
lfs->file_max = lfs->cfg->file_max;
if (!lfs->file_max) {
lfs->file_max = LFS_FILE_MAX;
}
LFS_ASSERT(lfs->cfg->attr_max <= LFS_ATTR_MAX);
lfs->attr_max = lfs->cfg->attr_max;
if (!lfs->attr_max) {
lfs->attr_max = LFS_ATTR_MAX;
}
LFS_ASSERT(lfs->cfg->metadata_max <= lfs->cfg->block_size);
// setup default state
lfs->root[0] = LFS_BLOCK_NULL;
lfs->root[1] = LFS_BLOCK_NULL;
lfs->mlist = NULL;
lfs->seed = 0;
lfs->gdisk = (lfs_gstate_t){0};
lfs->gstate = (lfs_gstate_t){0};
lfs->gdelta = (lfs_gstate_t){0};
#ifdef LFS_MIGRATE
lfs->lfs1 = NULL;
#endif
return 0;
cleanup:
lfs_deinit(lfs);
return err;
}
static int lfs_deinit(lfs_t *lfs) {
// free allocated memory
if (!lfs->cfg->read_buffer) {
lfs_free(lfs->rcache.buffer);
}
if (!lfs->cfg->prog_buffer) {
lfs_free(lfs->pcache.buffer);
}
if (!lfs->cfg->lookahead_buffer) {
lfs_free(lfs->free.buffer);
}
return 0;
}
#ifndef LFS_READONLY
static int lfs_rawformat(lfs_t *lfs, const struct lfs_config *cfg) {
int err = 0;
{
err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
lfs->free.off = 0;
lfs->free.size = lfs_min(8*lfs->cfg->lookahead_size,
lfs->cfg->block_count);
lfs->free.i = 0;
lfs_alloc_ack(lfs);
// create root dir
lfs_mdir_t root;
err = lfs_dir_alloc(lfs, &root);
if (err) {
goto cleanup;
}
// write one superblock
lfs_superblock_t superblock = {
.version = LFS_DISK_VERSION,
.block_size = lfs->cfg->block_size,
.block_count = lfs->cfg->block_count,
.name_max = lfs->name_max,
.file_max = lfs->file_max,
.attr_max = lfs->attr_max,
};
lfs_superblock_tole32(&superblock);
err = lfs_dir_commit(lfs, &root, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_CREATE, 0, 0), NULL},
{LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8), "littlefs"},
{LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock}));
if (err) {
goto cleanup;
}
// force compaction to prevent accidentally mounting any
// older version of littlefs that may live on disk
root.erased = false;
err = lfs_dir_commit(lfs, &root, NULL, 0);
if (err) {
goto cleanup;
}
// sanity check that fetch works
err = lfs_dir_fetch(lfs, &root, (const lfs_block_t[2]){0, 1});
if (err) {
goto cleanup;
}
}
cleanup:
lfs_deinit(lfs);
return err;
}
#endif
static int lfs_rawmount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// scan directory blocks for superblock and any global updates
lfs_mdir_t dir = {.tail = {0, 1}};
lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
lfs_size_t tortoise_i = 1;
lfs_size_t tortoise_period = 1;
while (!lfs_pair_isnull(dir.tail)) {
// detect cycles with Brent's algorithm
if (lfs_pair_issync(dir.tail, tortoise)) {
LFS_ERROR("Cycle detected in tail list");
err = LFS_ERR_CORRUPT;
goto cleanup;
}
if (tortoise_i == tortoise_period) {
tortoise[0] = dir.tail[0];
tortoise[1] = dir.tail[1];
tortoise_i = 0;
tortoise_period *= 2;
}
tortoise_i += 1;
// fetch next block in tail list
lfs_stag_t tag = lfs_dir_fetchmatch(lfs, &dir, dir.tail,
LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8),
NULL,
lfs_dir_find_match, &(struct lfs_dir_find_match){
lfs, "littlefs", 8});
if (tag < 0) {
err = tag;
goto cleanup;
}
// has superblock?
if (tag && !lfs_tag_isdelete(tag)) {
// update root
lfs->root[0] = dir.pair[0];
lfs->root[1] = dir.pair[1];
// grab superblock
lfs_superblock_t superblock;
tag = lfs_dir_get(lfs, &dir, LFS_MKTAG(0x7ff, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock);
if (tag < 0) {
err = tag;
goto cleanup;
}
lfs_superblock_fromle32(&superblock);
// check version
uint16_t major_version = (0xffff & (superblock.version >> 16));
uint16_t minor_version = (0xffff & (superblock.version >> 0));
if ((major_version != LFS_DISK_VERSION_MAJOR ||
minor_version > LFS_DISK_VERSION_MINOR)) {
LFS_ERROR("Invalid version v%"PRIu16".%"PRIu16,
major_version, minor_version);
err = LFS_ERR_INVAL;
goto cleanup;
}
// check superblock configuration
if (superblock.name_max) {
if (superblock.name_max > lfs->name_max) {
LFS_ERROR("Unsupported name_max (%"PRIu32" > %"PRIu32")",
superblock.name_max, lfs->name_max);
err = LFS_ERR_INVAL;
goto cleanup;
}
lfs->name_max = superblock.name_max;
}
if (superblock.file_max) {
if (superblock.file_max > lfs->file_max) {
LFS_ERROR("Unsupported file_max (%"PRIu32" > %"PRIu32")",
superblock.file_max, lfs->file_max);
err = LFS_ERR_INVAL;
goto cleanup;
}
lfs->file_max = superblock.file_max;
}
if (superblock.attr_max) {
if (superblock.attr_max > lfs->attr_max) {
LFS_ERROR("Unsupported attr_max (%"PRIu32" > %"PRIu32")",
superblock.attr_max, lfs->attr_max);
err = LFS_ERR_INVAL;
goto cleanup;
}
lfs->attr_max = superblock.attr_max;
}
if (superblock.block_count != lfs->cfg->block_count) {
LFS_ERROR("Invalid block count (%"PRIu32" != %"PRIu32")",
superblock.block_count, lfs->cfg->block_count);
err = LFS_ERR_INVAL;
goto cleanup;
}
if (superblock.block_size != lfs->cfg->block_size) {
LFS_ERROR("Invalid block size (%"PRIu32" != %"PRIu32")",
superblock.block_size, lfs->cfg->block_size);
err = LFS_ERR_INVAL;
goto cleanup;
}
}
// has gstate?
err = lfs_dir_getgstate(lfs, &dir, &lfs->gstate);
if (err) {
goto cleanup;
}
}
// found superblock?
if (lfs_pair_isnull(lfs->root)) {
err = LFS_ERR_INVAL;
goto cleanup;
}
// update littlefs with gstate
if (!lfs_gstate_iszero(&lfs->gstate)) {
LFS_DEBUG("Found pending gstate 0x%08"PRIx32"%08"PRIx32"%08"PRIx32,
lfs->gstate.tag,
lfs->gstate.pair[0],
lfs->gstate.pair[1]);
}
lfs->gstate.tag += !lfs_tag_isvalid(lfs->gstate.tag);
lfs->gdisk = lfs->gstate;
// setup free lookahead, to distribute allocations uniformly across
// boots, we start the allocator at a random location
lfs->free.off = lfs->seed % lfs->cfg->block_count;
lfs_alloc_drop(lfs);
return 0;
cleanup:
lfs_rawunmount(lfs);
return err;
}
static int lfs_rawunmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// Filesystem filesystem operations ///
int lfs_fs_rawtraverse(lfs_t *lfs,
int (*cb)(void *data, lfs_block_t block), void *data,
bool includeorphans) {
// iterate over metadata pairs
lfs_mdir_t dir = {.tail = {0, 1}};
#ifdef LFS_MIGRATE
// also consider v1 blocks during migration
if (lfs->lfs1) {
int err = lfs1_traverse(lfs, cb, data);
if (err) {
return err;
}
dir.tail[0] = lfs->root[0];
dir.tail[1] = lfs->root[1];
}
#endif
lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
lfs_size_t tortoise_i = 1;
lfs_size_t tortoise_period = 1;
while (!lfs_pair_isnull(dir.tail)) {
// detect cycles with Brent's algorithm
if (lfs_pair_issync(dir.tail, tortoise)) {
LFS_WARN("Cycle detected in tail list");
return LFS_ERR_CORRUPT;
}
if (tortoise_i == tortoise_period) {
tortoise[0] = dir.tail[0];
tortoise[1] = dir.tail[1];
tortoise_i = 0;
tortoise_period *= 2;
}
tortoise_i += 1;
for (int i = 0; i < 2; i++) {
int err = cb(data, dir.tail[i]);
if (err) {
return err;
}
}
// iterate through ids in directory
int err = lfs_dir_fetch(lfs, &dir, dir.tail);
if (err) {
return err;
}
for (uint16_t id = 0; id < dir.count; id++) {
struct lfs_ctz ctz;
lfs_stag_t tag = lfs_dir_get(lfs, &dir, LFS_MKTAG(0x700, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, id, sizeof(ctz)), &ctz);
if (tag < 0) {
if (tag == LFS_ERR_NOENT) {
continue;
}
return tag;
}
lfs_ctz_fromle32(&ctz);
if (lfs_tag_type3(tag) == LFS_TYPE_CTZSTRUCT) {
err = lfs_ctz_traverse(lfs, NULL, &lfs->rcache,
ctz.head, ctz.size, cb, data);
if (err) {
return err;
}
} else if (includeorphans &&
lfs_tag_type3(tag) == LFS_TYPE_DIRSTRUCT) {
for (int i = 0; i < 2; i++) {
err = cb(data, (&ctz.head)[i]);
if (err) {
return err;
}
}
}
}
}
#ifndef LFS_READONLY
// iterate over any open files
for (lfs_file_t *f = (lfs_file_t*)lfs->mlist; f; f = f->next) {
if (f->type != LFS_TYPE_REG) {
continue;
}
if ((f->flags & LFS_F_DIRTY) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
f->ctz.head, f->ctz.size, cb, data);
if (err) {
return err;
}
}
if ((f->flags & LFS_F_WRITING) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
f->block, f->pos, cb, data);
if (err) {
return err;
}
}
}
#endif
return 0;
}
#ifndef LFS_READONLY
static int lfs_fs_pred(lfs_t *lfs,
const lfs_block_t pair[2], lfs_mdir_t *pdir) {
// iterate over all directory directory entries
pdir->tail[0] = 0;
pdir->tail[1] = 1;
lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
lfs_size_t tortoise_i = 1;
lfs_size_t tortoise_period = 1;
while (!lfs_pair_isnull(pdir->tail)) {
// detect cycles with Brent's algorithm
if (lfs_pair_issync(pdir->tail, tortoise)) {
LFS_WARN("Cycle detected in tail list");
return LFS_ERR_CORRUPT;
}
if (tortoise_i == tortoise_period) {
tortoise[0] = pdir->tail[0];
tortoise[1] = pdir->tail[1];
tortoise_i = 0;
tortoise_period *= 2;
}
tortoise_i += 1;
if (lfs_pair_cmp(pdir->tail, pair) == 0) {
return 0;
}
int err = lfs_dir_fetch(lfs, pdir, pdir->tail);
if (err) {
return err;
}
}
return LFS_ERR_NOENT;
}
#endif
#ifndef LFS_READONLY
struct lfs_fs_parent_match {
lfs_t *lfs;
const lfs_block_t pair[2];
};
#endif
#ifndef LFS_READONLY
static int lfs_fs_parent_match(void *data,
lfs_tag_t tag, const void *buffer) {
struct lfs_fs_parent_match *find = data;
lfs_t *lfs = find->lfs;
const struct lfs_diskoff *disk = buffer;
(void)tag;
lfs_block_t child[2];
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
disk->block, disk->off, &child, sizeof(child));
if (err) {
return err;
}
lfs_pair_fromle32(child);
return (lfs_pair_cmp(child, find->pair) == 0) ? LFS_CMP_EQ : LFS_CMP_LT;
}
#endif
#ifndef LFS_READONLY
static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
lfs_mdir_t *parent) {
// use fetchmatch with callback to find pairs
parent->tail[0] = 0;
parent->tail[1] = 1;
lfs_block_t tortoise[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
lfs_size_t tortoise_i = 1;
lfs_size_t tortoise_period = 1;
while (!lfs_pair_isnull(parent->tail)) {
// detect cycles with Brent's algorithm
if (lfs_pair_issync(parent->tail, tortoise)) {
LFS_WARN("Cycle detected in tail list");
return LFS_ERR_CORRUPT;
}
if (tortoise_i == tortoise_period) {
tortoise[0] = parent->tail[0];
tortoise[1] = parent->tail[1];
tortoise_i = 0;
tortoise_period *= 2;
}
tortoise_i += 1;
lfs_stag_t tag = lfs_dir_fetchmatch(lfs, parent, parent->tail,
LFS_MKTAG(0x7ff, 0, 0x3ff),
LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, 8),
NULL,
lfs_fs_parent_match, &(struct lfs_fs_parent_match){
lfs, {pair[0], pair[1]}});
if (tag && tag != LFS_ERR_NOENT) {
return tag;
}
}
return LFS_ERR_NOENT;
}
#endif
#ifndef LFS_READONLY
static int lfs_fs_preporphans(lfs_t *lfs, int8_t orphans) {
LFS_ASSERT(lfs_tag_size(lfs->gstate.tag) > 0x000 || orphans >= 0);
LFS_ASSERT(lfs_tag_size(lfs->gstate.tag) < 0x3ff || orphans <= 0);
lfs->gstate.tag += orphans;
lfs->gstate.tag = ((lfs->gstate.tag & ~LFS_MKTAG(0x800, 0, 0)) |
((uint32_t)lfs_gstate_hasorphans(&lfs->gstate) << 31));
return 0;
}
#endif
#ifndef LFS_READONLY
static void lfs_fs_prepmove(lfs_t *lfs,
uint16_t id, const lfs_block_t pair[2]) {
lfs->gstate.tag = ((lfs->gstate.tag & ~LFS_MKTAG(0x7ff, 0x3ff, 0)) |
((id != 0x3ff) ? LFS_MKTAG(LFS_TYPE_DELETE, id, 0) : 0));
lfs->gstate.pair[0] = (id != 0x3ff) ? pair[0] : 0;
lfs->gstate.pair[1] = (id != 0x3ff) ? pair[1] : 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_fs_demove(lfs_t *lfs) {
if (!lfs_gstate_hasmove(&lfs->gdisk)) {
return 0;
}
// Fix bad moves
LFS_DEBUG("Fixing move {0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16,
lfs->gdisk.pair[0],
lfs->gdisk.pair[1],
lfs_tag_id(lfs->gdisk.tag));
// no other gstate is supported at this time, so if we found something else
// something most likely went wrong in gstate calculation
LFS_ASSERT(lfs_tag_type3(lfs->gdisk.tag) == LFS_TYPE_DELETE);
// fetch and delete the moved entry
lfs_mdir_t movedir;
int err = lfs_dir_fetch(lfs, &movedir, lfs->gdisk.pair);
if (err) {
return err;
}
// prep gstate and delete move id
uint16_t moveid = lfs_tag_id(lfs->gdisk.tag);
lfs_fs_prepmove(lfs, 0x3ff, NULL);
err = lfs_dir_commit(lfs, &movedir, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_DELETE, moveid, 0), NULL}));
if (err) {
return err;
}
return 0;
}
#endif
#ifndef LFS_READONLY
static int lfs_fs_deorphan(lfs_t *lfs, bool powerloss) {
if (!lfs_gstate_hasorphans(&lfs->gstate)) {
return 0;
}
int8_t found = 0;
// Check for orphans in two separate passes:
// - 1 for half-orphans (relocations)
// - 2 for full-orphans (removes/renames)
//
// Two separate passes are needed as half-orphans can contain outdated
// references to full-orphans, effectively hiding them from the deorphan
// search.
//
int pass = 0;
while (pass < 2) {
// Fix any orphans
lfs_mdir_t pdir = {.split = true, .tail = {0, 1}};
lfs_mdir_t dir;
bool moreorphans = false;
// iterate over all directory directory entries
while (!lfs_pair_isnull(pdir.tail)) {
int err = lfs_dir_fetch(lfs, &dir, pdir.tail);
if (err) {
return err;
}
// check head blocks for orphans
if (!pdir.split) {
// check if we have a parent
lfs_mdir_t parent;
lfs_stag_t tag = lfs_fs_parent(lfs, pdir.tail, &parent);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
if (pass == 0 && tag != LFS_ERR_NOENT) {
lfs_block_t pair[2];
lfs_stag_t state = lfs_dir_get(lfs, &parent,
LFS_MKTAG(0x7ff, 0x3ff, 0), tag, pair);
if (state < 0) {
return state;
}
lfs_pair_fromle32(pair);
if (!lfs_pair_issync(pair, pdir.tail)) {
// we have desynced
LFS_DEBUG("Fixing half-orphan "
"{0x%"PRIx32", 0x%"PRIx32"} "
"-> {0x%"PRIx32", 0x%"PRIx32"}",
pdir.tail[0], pdir.tail[1], pair[0], pair[1]);
// fix pending move in this pair? this looks like an
// optimization but is in fact _required_ since
// relocating may outdate the move.
uint16_t moveid = 0x3ff;
if (lfs_gstate_hasmovehere(&lfs->gstate, pdir.pair)) {
moveid = lfs_tag_id(lfs->gstate.tag);
LFS_DEBUG("Fixing move while fixing orphans "
"{0x%"PRIx32", 0x%"PRIx32"} 0x%"PRIx16"\n",
pdir.pair[0], pdir.pair[1], moveid);
lfs_fs_prepmove(lfs, 0x3ff, NULL);
}
lfs_pair_tole32(pair);
state = lfs_dir_orphaningcommit(lfs, &pdir, LFS_MKATTRS(
{LFS_MKTAG_IF(moveid != 0x3ff,
LFS_TYPE_DELETE, moveid, 0), NULL},
{LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 8),
pair}));
lfs_pair_fromle32(pair);
if (state < 0) {
return state;
}
found += 1;
// did our commit create more orphans?
if (state == LFS_OK_ORPHANED) {
moreorphans = true;
}
// refetch tail
continue;
}
}
// note we only check for full orphans if we may have had a
// power-loss, otherwise orphans are created intentionally
// during operations such as lfs_mkdir
if (pass == 1 && tag == LFS_ERR_NOENT && powerloss) {
// we are an orphan
LFS_DEBUG("Fixing orphan {0x%"PRIx32", 0x%"PRIx32"}",
pdir.tail[0], pdir.tail[1]);
// steal state
err = lfs_dir_getgstate(lfs, &dir, &lfs->gdelta);
if (err) {
return err;
}
// steal tail
lfs_pair_tole32(dir.tail);
int state = lfs_dir_orphaningcommit(lfs, &pdir, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_TAIL + dir.split, 0x3ff, 8),
dir.tail}));
lfs_pair_fromle32(dir.tail);
if (state < 0) {
return state;
}
found += 1;
// did our commit create more orphans?
if (state == LFS_OK_ORPHANED) {
moreorphans = true;
}
// refetch tail
continue;
}
}
pdir = dir;
}
pass = moreorphans ? 0 : pass+1;
}
// mark orphans as fixed
return lfs_fs_preporphans(lfs, -lfs_min(
lfs_gstate_getorphans(&lfs->gstate),
found));
}
#endif
#ifndef LFS_READONLY
static int lfs_fs_forceconsistency(lfs_t *lfs) {
int err = lfs_fs_demove(lfs);
if (err) {
return err;
}
err = lfs_fs_deorphan(lfs, true);
if (err) {
return err;
}
return 0;
}
#endif
static int lfs_fs_size_count(void *p, lfs_block_t block) {
(void)block;
lfs_size_t *size = p;
*size += 1;
return 0;
}
static lfs_ssize_t lfs_fs_rawsize(lfs_t *lfs) {
lfs_size_t size = 0;
int err = lfs_fs_rawtraverse(lfs, lfs_fs_size_count, &size, false);
if (err) {
return err;
}
return size;
}
#ifdef LFS_MIGRATE
////// Migration from littelfs v1 below this //////
/// Version info ///
// Software library version
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS1_VERSION 0x00010007
#define LFS1_VERSION_MAJOR (0xffff & (LFS1_VERSION >> 16))
#define LFS1_VERSION_MINOR (0xffff & (LFS1_VERSION >> 0))
// Version of On-disk data structures
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS1_DISK_VERSION 0x00010001
#define LFS1_DISK_VERSION_MAJOR (0xffff & (LFS1_DISK_VERSION >> 16))
#define LFS1_DISK_VERSION_MINOR (0xffff & (LFS1_DISK_VERSION >> 0))
/// v1 Definitions ///
// File types
enum lfs1_type {
LFS1_TYPE_REG = 0x11,
LFS1_TYPE_DIR = 0x22,
LFS1_TYPE_SUPERBLOCK = 0x2e,
};
typedef struct lfs1 {
lfs_block_t root[2];
} lfs1_t;
typedef struct lfs1_entry {
lfs_off_t off;
struct lfs1_disk_entry {
uint8_t type;
uint8_t elen;
uint8_t alen;
uint8_t nlen;
union {
struct {
lfs_block_t head;
lfs_size_t size;
} file;
lfs_block_t dir[2];
} u;
} d;
} lfs1_entry_t;
typedef struct lfs1_dir {
struct lfs1_dir *next;
lfs_block_t pair[2];
lfs_off_t off;
lfs_block_t head[2];
lfs_off_t pos;
struct lfs1_disk_dir {
uint32_t rev;
lfs_size_t size;
lfs_block_t tail[2];
} d;
} lfs1_dir_t;
typedef struct lfs1_superblock {
lfs_off_t off;
struct lfs1_disk_superblock {
uint8_t type;
uint8_t elen;
uint8_t alen;
uint8_t nlen;
lfs_block_t root[2];
uint32_t block_size;
uint32_t block_count;
uint32_t version;
char magic[8];
} d;
} lfs1_superblock_t;
/// Low-level wrappers v1->v2 ///
static void lfs1_crc(uint32_t *crc, const void *buffer, size_t size) {
*crc = lfs_crc(*crc, buffer, size);
}
static int lfs1_bd_read(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
// if we ever do more than writes to alternating pairs,
// this may need to consider pcache
return lfs_bd_read(lfs, &lfs->pcache, &lfs->rcache, size,
block, off, buffer, size);
}
static int lfs1_bd_crc(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, lfs_size_t size, uint32_t *crc) {
for (lfs_off_t i = 0; i < size; i++) {
uint8_t c;
int err = lfs1_bd_read(lfs, block, off+i, &c, 1);
if (err) {
return err;
}
lfs1_crc(crc, &c, 1);
}
return 0;
}
/// Endian swapping functions ///
static void lfs1_dir_fromle32(struct lfs1_disk_dir *d) {
d->rev = lfs_fromle32(d->rev);
d->size = lfs_fromle32(d->size);
d->tail[0] = lfs_fromle32(d->tail[0]);
d->tail[1] = lfs_fromle32(d->tail[1]);
}
static void lfs1_dir_tole32(struct lfs1_disk_dir *d) {
d->rev = lfs_tole32(d->rev);
d->size = lfs_tole32(d->size);
d->tail[0] = lfs_tole32(d->tail[0]);
d->tail[1] = lfs_tole32(d->tail[1]);
}
static void lfs1_entry_fromle32(struct lfs1_disk_entry *d) {
d->u.dir[0] = lfs_fromle32(d->u.dir[0]);
d->u.dir[1] = lfs_fromle32(d->u.dir[1]);
}
static void lfs1_entry_tole32(struct lfs1_disk_entry *d) {
d->u.dir[0] = lfs_tole32(d->u.dir[0]);
d->u.dir[1] = lfs_tole32(d->u.dir[1]);
}
static void lfs1_superblock_fromle32(struct lfs1_disk_superblock *d) {
d->root[0] = lfs_fromle32(d->root[0]);
d->root[1] = lfs_fromle32(d->root[1]);
d->block_size = lfs_fromle32(d->block_size);
d->block_count = lfs_fromle32(d->block_count);
d->version = lfs_fromle32(d->version);
}
///// Metadata pair and directory operations ///
static inline lfs_size_t lfs1_entry_size(const lfs1_entry_t *entry) {
return 4 + entry->d.elen + entry->d.alen + entry->d.nlen;
}
static int lfs1_dir_fetch(lfs_t *lfs,
lfs1_dir_t *dir, const lfs_block_t pair[2]) {
// copy out pair, otherwise may be aliasing dir
const lfs_block_t tpair[2] = {pair[0], pair[1]};
bool valid = false;
// check both blocks for the most recent revision
for (int i = 0; i < 2; i++) {
struct lfs1_disk_dir test;
int err = lfs1_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
lfs1_dir_fromle32(&test);
if (err) {
if (err == LFS_ERR_CORRUPT) {
continue;
}
return err;
}
if (valid && lfs_scmp(test.rev, dir->d.rev) < 0) {
continue;
}
if ((0x7fffffff & test.size) < sizeof(test)+4 ||
(0x7fffffff & test.size) > lfs->cfg->block_size) {
continue;
}
uint32_t crc = 0xffffffff;
lfs1_dir_tole32(&test);
lfs1_crc(&crc, &test, sizeof(test));
lfs1_dir_fromle32(&test);
err = lfs1_bd_crc(lfs, tpair[i], sizeof(test),
(0x7fffffff & test.size) - sizeof(test), &crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
continue;
}
return err;
}
if (crc != 0) {
continue;
}
valid = true;
// setup dir in case it's valid
dir->pair[0] = tpair[(i+0) % 2];
dir->pair[1] = tpair[(i+1) % 2];
dir->off = sizeof(dir->d);
dir->d = test;
}
if (!valid) {
LFS_ERROR("Corrupted dir pair at {0x%"PRIx32", 0x%"PRIx32"}",
tpair[0], tpair[1]);
return LFS_ERR_CORRUPT;
}
return 0;
}
static int lfs1_dir_next(lfs_t *lfs, lfs1_dir_t *dir, lfs1_entry_t *entry) {
while (dir->off + sizeof(entry->d) > (0x7fffffff & dir->d.size)-4) {
if (!(0x80000000 & dir->d.size)) {
entry->off = dir->off;
return LFS_ERR_NOENT;
}
int err = lfs1_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
dir->off = sizeof(dir->d);
dir->pos += sizeof(dir->d) + 4;
}
int err = lfs1_bd_read(lfs, dir->pair[0], dir->off,
&entry->d, sizeof(entry->d));
lfs1_entry_fromle32(&entry->d);
if (err) {
return err;
}
entry->off = dir->off;
dir->off += lfs1_entry_size(entry);
dir->pos += lfs1_entry_size(entry);
return 0;
}
/// littlefs v1 specific operations ///
int lfs1_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
if (lfs_pair_isnull(lfs->lfs1->root)) {
return 0;
}
// iterate over metadata pairs
lfs1_dir_t dir;
lfs1_entry_t entry;
lfs_block_t cwd[2] = {0, 1};
while (true) {
for (int i = 0; i < 2; i++) {
int err = cb(data, cwd[i]);
if (err) {
return err;
}
}
int err = lfs1_dir_fetch(lfs, &dir, cwd);
if (err) {
return err;
}
// iterate over contents
while (dir.off + sizeof(entry.d) <= (0x7fffffff & dir.d.size)-4) {
err = lfs1_bd_read(lfs, dir.pair[0], dir.off,
&entry.d, sizeof(entry.d));
lfs1_entry_fromle32(&entry.d);
if (err) {
return err;
}
dir.off += lfs1_entry_size(&entry);
if ((0x70 & entry.d.type) == (0x70 & LFS1_TYPE_REG)) {
err = lfs_ctz_traverse(lfs, NULL, &lfs->rcache,
entry.d.u.file.head, entry.d.u.file.size, cb, data);
if (err) {
return err;
}
}
}
// we also need to check if we contain a threaded v2 directory
lfs_mdir_t dir2 = {.split=true, .tail={cwd[0], cwd[1]}};
while (dir2.split) {
err = lfs_dir_fetch(lfs, &dir2, dir2.tail);
if (err) {
break;
}
for (int i = 0; i < 2; i++) {
err = cb(data, dir2.pair[i]);
if (err) {
return err;
}
}
}
cwd[0] = dir.d.tail[0];
cwd[1] = dir.d.tail[1];
if (lfs_pair_isnull(cwd)) {
break;
}
}
return 0;
}
static int lfs1_moved(lfs_t *lfs, const void *e) {
if (lfs_pair_isnull(lfs->lfs1->root)) {
return 0;
}
// skip superblock
lfs1_dir_t cwd;
int err = lfs1_dir_fetch(lfs, &cwd, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
// iterate over all directory directory entries
lfs1_entry_t entry;
while (!lfs_pair_isnull(cwd.d.tail)) {
err = lfs1_dir_fetch(lfs, &cwd, cwd.d.tail);
if (err) {
return err;
}
while (true) {
err = lfs1_dir_next(lfs, &cwd, &entry);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
if (!(0x80 & entry.d.type) &&
memcmp(&entry.d.u, e, sizeof(entry.d.u)) == 0) {
return true;
}
}
}
return false;
}
/// Filesystem operations ///
static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
const struct lfs_config *cfg) {
int err = 0;
{
err = lfs_init(lfs, cfg);
if (err) {
return err;
}
lfs->lfs1 = lfs1;
lfs->lfs1->root[0] = LFS_BLOCK_NULL;
lfs->lfs1->root[1] = LFS_BLOCK_NULL;
// setup free lookahead
lfs->free.off = 0;
lfs->free.size = 0;
lfs->free.i = 0;
lfs_alloc_ack(lfs);
// load superblock
lfs1_dir_t dir;
lfs1_superblock_t superblock;
err = lfs1_dir_fetch(lfs, &dir, (const lfs_block_t[2]){0, 1});
if (err && err != LFS_ERR_CORRUPT) {
goto cleanup;
}
if (!err) {
err = lfs1_bd_read(lfs, dir.pair[0], sizeof(dir.d),
&superblock.d, sizeof(superblock.d));
lfs1_superblock_fromle32(&superblock.d);
if (err) {
goto cleanup;
}
lfs->lfs1->root[0] = superblock.d.root[0];
lfs->lfs1->root[1] = superblock.d.root[1];
}
if (err || memcmp(superblock.d.magic, "littlefs", 8) != 0) {
LFS_ERROR("Invalid superblock at {0x%"PRIx32", 0x%"PRIx32"}",
0, 1);
err = LFS_ERR_CORRUPT;
goto cleanup;
}
uint16_t major_version = (0xffff & (superblock.d.version >> 16));
uint16_t minor_version = (0xffff & (superblock.d.version >> 0));
if ((major_version != LFS1_DISK_VERSION_MAJOR ||
minor_version > LFS1_DISK_VERSION_MINOR)) {
LFS_ERROR("Invalid version v%d.%d", major_version, minor_version);
err = LFS_ERR_INVAL;
goto cleanup;
}
return 0;
}
cleanup:
lfs_deinit(lfs);
return err;
}
static int lfs1_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// v1 migration ///
static int lfs_rawmigrate(lfs_t *lfs, const struct lfs_config *cfg) {
struct lfs1 lfs1;
int err = lfs1_mount(lfs, &lfs1, cfg);
if (err) {
return err;
}
{
// iterate through each directory, copying over entries
// into new directory
lfs1_dir_t dir1;
lfs_mdir_t dir2;
dir1.d.tail[0] = lfs->lfs1->root[0];
dir1.d.tail[1] = lfs->lfs1->root[1];
while (!lfs_pair_isnull(dir1.d.tail)) {
// iterate old dir
err = lfs1_dir_fetch(lfs, &dir1, dir1.d.tail);
if (err) {
goto cleanup;
}
// create new dir and bind as temporary pretend root
err = lfs_dir_alloc(lfs, &dir2);
if (err) {
goto cleanup;
}
dir2.rev = dir1.d.rev;
dir1.head[0] = dir1.pair[0];
dir1.head[1] = dir1.pair[1];
lfs->root[0] = dir2.pair[0];
lfs->root[1] = dir2.pair[1];
err = lfs_dir_commit(lfs, &dir2, NULL, 0);
if (err) {
goto cleanup;
}
while (true) {
lfs1_entry_t entry1;
err = lfs1_dir_next(lfs, &dir1, &entry1);
if (err && err != LFS_ERR_NOENT) {
goto cleanup;
}
if (err == LFS_ERR_NOENT) {
break;
}
// check that entry has not been moved
if (entry1.d.type & 0x80) {
int moved = lfs1_moved(lfs, &entry1.d.u);
if (moved < 0) {
err = moved;
goto cleanup;
}
if (moved) {
continue;
}
entry1.d.type &= ~0x80;
}
// also fetch name
char name[LFS_NAME_MAX+1];
memset(name, 0, sizeof(name));
err = lfs1_bd_read(lfs, dir1.pair[0],
entry1.off + 4+entry1.d.elen+entry1.d.alen,
name, entry1.d.nlen);
if (err) {
goto cleanup;
}
bool isdir = (entry1.d.type == LFS1_TYPE_DIR);
// create entry in new dir
err = lfs_dir_fetch(lfs, &dir2, lfs->root);
if (err) {
goto cleanup;
}
uint16_t id;
err = lfs_dir_find(lfs, &dir2, &(const char*){name}, &id);
if (!(err == LFS_ERR_NOENT && id != 0x3ff)) {
err = (err < 0) ? err : LFS_ERR_EXIST;
goto cleanup;
}
lfs1_entry_tole32(&entry1.d);
err = lfs_dir_commit(lfs, &dir2, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_CREATE, id, 0), NULL},
{LFS_MKTAG_IF_ELSE(isdir,
LFS_TYPE_DIR, id, entry1.d.nlen,
LFS_TYPE_REG, id, entry1.d.nlen),
name},
{LFS_MKTAG_IF_ELSE(isdir,
LFS_TYPE_DIRSTRUCT, id, sizeof(entry1.d.u),
LFS_TYPE_CTZSTRUCT, id, sizeof(entry1.d.u)),
&entry1.d.u}));
lfs1_entry_fromle32(&entry1.d);
if (err) {
goto cleanup;
}
}
if (!lfs_pair_isnull(dir1.d.tail)) {
// find last block and update tail to thread into fs
err = lfs_dir_fetch(lfs, &dir2, lfs->root);
if (err) {
goto cleanup;
}
while (dir2.split) {
err = lfs_dir_fetch(lfs, &dir2, dir2.tail);
if (err) {
goto cleanup;
}
}
lfs_pair_tole32(dir2.pair);
err = lfs_dir_commit(lfs, &dir2, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 8), dir1.d.tail}));
lfs_pair_fromle32(dir2.pair);
if (err) {
goto cleanup;
}
}
// Copy over first block to thread into fs. Unfortunately
// if this fails there is not much we can do.
LFS_DEBUG("Migrating {0x%"PRIx32", 0x%"PRIx32"} "
"-> {0x%"PRIx32", 0x%"PRIx32"}",
lfs->root[0], lfs->root[1], dir1.head[0], dir1.head[1]);
err = lfs_bd_erase(lfs, dir1.head[1]);
if (err) {
goto cleanup;
}
err = lfs_dir_fetch(lfs, &dir2, lfs->root);
if (err) {
goto cleanup;
}
for (lfs_off_t i = 0; i < dir2.off; i++) {
uint8_t dat;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, dir2.off,
dir2.pair[0], i, &dat, 1);
if (err) {
goto cleanup;
}
err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, true,
dir1.head[1], i, &dat, 1);
if (err) {
goto cleanup;
}
}
err = lfs_bd_flush(lfs, &lfs->pcache, &lfs->rcache, true);
if (err) {
goto cleanup;
}
}
// Create new superblock. This marks a successful migration!
err = lfs1_dir_fetch(lfs, &dir1, (const lfs_block_t[2]){0, 1});
if (err) {
goto cleanup;
}
dir2.pair[0] = dir1.pair[0];
dir2.pair[1] = dir1.pair[1];
dir2.rev = dir1.d.rev;
dir2.off = sizeof(dir2.rev);
dir2.etag = 0xffffffff;
dir2.count = 0;
dir2.tail[0] = lfs->lfs1->root[0];
dir2.tail[1] = lfs->lfs1->root[1];
dir2.erased = false;
dir2.split = true;
lfs_superblock_t superblock = {
.version = LFS_DISK_VERSION,
.block_size = lfs->cfg->block_size,
.block_count = lfs->cfg->block_count,
.name_max = lfs->name_max,
.file_max = lfs->file_max,
.attr_max = lfs->attr_max,
};
lfs_superblock_tole32(&superblock);
err = lfs_dir_commit(lfs, &dir2, LFS_MKATTRS(
{LFS_MKTAG(LFS_TYPE_CREATE, 0, 0), NULL},
{LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8), "littlefs"},
{LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, sizeof(superblock)),
&superblock}));
if (err) {
goto cleanup;
}
// sanity check that fetch works
err = lfs_dir_fetch(lfs, &dir2, (const lfs_block_t[2]){0, 1});
if (err) {
goto cleanup;
}
// force compaction to prevent accidentally mounting v1
dir2.erased = false;
err = lfs_dir_commit(lfs, &dir2, NULL, 0);
if (err) {
goto cleanup;
}
}
cleanup:
lfs1_unmount(lfs);
return err;
}
#endif
/// Public API wrappers ///
// Here we can add tracing/thread safety easily
// Thread-safe wrappers if enabled
#ifdef LFS_THREADSAFE
#define LFS_LOCK(cfg) cfg->lock(cfg)
#define LFS_UNLOCK(cfg) cfg->unlock(cfg)
#else
#define LFS_LOCK(cfg) ((void)cfg, 0)
#define LFS_UNLOCK(cfg) ((void)cfg)
#endif
// Public API
#ifndef LFS_READONLY
int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = LFS_LOCK(cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_format(%p, %p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p, "
".read_size=%"PRIu32", .prog_size=%"PRIu32", "
".block_size=%"PRIu32", .block_count=%"PRIu32", "
".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
".lookahead_size=%"PRIu32", .read_buffer=%p, "
".prog_buffer=%p, .lookahead_buffer=%p, "
".name_max=%"PRIu32", .file_max=%"PRIu32", "
".attr_max=%"PRIu32"})",
(void*)lfs, (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,
cfg->block_cycles, cfg->cache_size, cfg->lookahead_size,
cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
cfg->name_max, cfg->file_max, cfg->attr_max);
err = lfs_rawformat(lfs, cfg);
LFS_TRACE("lfs_format -> %d", err);
LFS_UNLOCK(cfg);
return err;
}
#endif
int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = LFS_LOCK(cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_mount(%p, %p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p, "
".read_size=%"PRIu32", .prog_size=%"PRIu32", "
".block_size=%"PRIu32", .block_count=%"PRIu32", "
".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
".lookahead_size=%"PRIu32", .read_buffer=%p, "
".prog_buffer=%p, .lookahead_buffer=%p, "
".name_max=%"PRIu32", .file_max=%"PRIu32", "
".attr_max=%"PRIu32"})",
(void*)lfs, (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,
cfg->block_cycles, cfg->cache_size, cfg->lookahead_size,
cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
cfg->name_max, cfg->file_max, cfg->attr_max);
err = lfs_rawmount(lfs, cfg);
LFS_TRACE("lfs_mount -> %d", err);
LFS_UNLOCK(cfg);
return err;
}
int lfs_unmount(lfs_t *lfs) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_unmount(%p)", (void*)lfs);
err = lfs_rawunmount(lfs);
LFS_TRACE("lfs_unmount -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#ifndef LFS_READONLY
int lfs_remove(lfs_t *lfs, const char *path) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_remove(%p, \"%s\")", (void*)lfs, path);
err = lfs_rawremove(lfs, path);
LFS_TRACE("lfs_remove -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
#ifndef LFS_READONLY
int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_rename(%p, \"%s\", \"%s\")", (void*)lfs, oldpath, newpath);
err = lfs_rawrename(lfs, oldpath, newpath);
LFS_TRACE("lfs_rename -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_stat(%p, \"%s\", %p)", (void*)lfs, path, (void*)info);
err = lfs_rawstat(lfs, path, info);
LFS_TRACE("lfs_stat -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
uint8_t type, void *buffer, lfs_size_t size) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_getattr(%p, \"%s\", %"PRIu8", %p, %"PRIu32")",
(void*)lfs, path, type, buffer, size);
lfs_ssize_t res = lfs_rawgetattr(lfs, path, type, buffer, size);
LFS_TRACE("lfs_getattr -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
#ifndef LFS_READONLY
int lfs_setattr(lfs_t *lfs, const char *path,
uint8_t type, const void *buffer, lfs_size_t size) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_setattr(%p, \"%s\", %"PRIu8", %p, %"PRIu32")",
(void*)lfs, path, type, buffer, size);
err = lfs_rawsetattr(lfs, path, type, buffer, size);
LFS_TRACE("lfs_setattr -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
#ifndef LFS_READONLY
int lfs_removeattr(lfs_t *lfs, const char *path, uint8_t type) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_removeattr(%p, \"%s\", %"PRIu8")", (void*)lfs, path, type);
err = lfs_rawremoveattr(lfs, path, type);
LFS_TRACE("lfs_removeattr -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
#ifndef LFS_NO_MALLOC
int lfs_file_open(lfs_t *lfs, lfs_file_t *file, const char *path, int flags) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_open(%p, %p, \"%s\", %x)",
(void*)lfs, (void*)file, path, flags);
LFS_ASSERT(!lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
err = lfs_file_rawopen(lfs, file, path, flags);
LFS_TRACE("lfs_file_open -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags,
const struct lfs_file_config *cfg) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_opencfg(%p, %p, \"%s\", %x, %p {"
".buffer=%p, .attrs=%p, .attr_count=%"PRIu32"})",
(void*)lfs, (void*)file, path, flags,
(void*)cfg, cfg->buffer, (void*)cfg->attrs, cfg->attr_count);
LFS_ASSERT(!lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
err = lfs_file_rawopencfg(lfs, file, path, flags, cfg);
LFS_TRACE("lfs_file_opencfg -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_close(%p, %p)", (void*)lfs, (void*)file);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
err = lfs_file_rawclose(lfs, file);
LFS_TRACE("lfs_file_close -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#ifndef LFS_READONLY
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_sync(%p, %p)", (void*)lfs, (void*)file);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
err = lfs_file_rawsync(lfs, file);
LFS_TRACE("lfs_file_sync -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_read(%p, %p, %p, %"PRIu32")",
(void*)lfs, (void*)file, buffer, size);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
lfs_ssize_t res = lfs_file_rawread(lfs, file, buffer, size);
LFS_TRACE("lfs_file_read -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
#ifndef LFS_READONLY
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_write(%p, %p, %p, %"PRIu32")",
(void*)lfs, (void*)file, buffer, size);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
lfs_ssize_t res = lfs_file_rawwrite(lfs, file, buffer, size);
LFS_TRACE("lfs_file_write -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
#endif
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_seek(%p, %p, %"PRId32", %d)",
(void*)lfs, (void*)file, off, whence);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
lfs_soff_t res = lfs_file_rawseek(lfs, file, off, whence);
LFS_TRACE("lfs_file_seek -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
#ifndef LFS_READONLY
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_truncate(%p, %p, %"PRIu32")",
(void*)lfs, (void*)file, size);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
err = lfs_file_rawtruncate(lfs, file, size);
LFS_TRACE("lfs_file_truncate -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_tell(%p, %p)", (void*)lfs, (void*)file);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
lfs_soff_t res = lfs_file_rawtell(lfs, file);
LFS_TRACE("lfs_file_tell -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_rewind(%p, %p)", (void*)lfs, (void*)file);
err = lfs_file_rawrewind(lfs, file);
LFS_TRACE("lfs_file_rewind -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_file_size(%p, %p)", (void*)lfs, (void*)file);
LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
lfs_soff_t res = lfs_file_rawsize(lfs, file);
LFS_TRACE("lfs_file_size -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
#ifndef LFS_READONLY
int lfs_mkdir(lfs_t *lfs, const char *path) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_mkdir(%p, \"%s\")", (void*)lfs, path);
err = lfs_rawmkdir(lfs, path);
LFS_TRACE("lfs_mkdir -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#endif
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_open(%p, %p, \"%s\")", (void*)lfs, (void*)dir, path);
LFS_ASSERT(!lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)dir));
err = lfs_dir_rawopen(lfs, dir, path);
LFS_TRACE("lfs_dir_open -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_close(%p, %p)", (void*)lfs, (void*)dir);
err = lfs_dir_rawclose(lfs, dir);
LFS_TRACE("lfs_dir_close -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_read(%p, %p, %p)",
(void*)lfs, (void*)dir, (void*)info);
err = lfs_dir_rawread(lfs, dir, info);
LFS_TRACE("lfs_dir_read -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_seek(%p, %p, %"PRIu32")",
(void*)lfs, (void*)dir, off);
err = lfs_dir_rawseek(lfs, dir, off);
LFS_TRACE("lfs_dir_seek -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_tell(%p, %p)", (void*)lfs, (void*)dir);
lfs_soff_t res = lfs_dir_rawtell(lfs, dir);
LFS_TRACE("lfs_dir_tell -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_dir_rewind(%p, %p)", (void*)lfs, (void*)dir);
err = lfs_dir_rawrewind(lfs, dir);
LFS_TRACE("lfs_dir_rewind -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_fs_size(%p)", (void*)lfs);
lfs_ssize_t res = lfs_fs_rawsize(lfs);
LFS_TRACE("lfs_fs_size -> %"PRId32, res);
LFS_UNLOCK(lfs->cfg);
return res;
}
int lfs_fs_traverse(lfs_t *lfs, int (*cb)(void *, lfs_block_t), void *data) {
int err = LFS_LOCK(lfs->cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_fs_traverse(%p, %p, %p)",
(void*)lfs, (void*)(uintptr_t)cb, data);
err = lfs_fs_rawtraverse(lfs, cb, data, true);
LFS_TRACE("lfs_fs_traverse -> %d", err);
LFS_UNLOCK(lfs->cfg);
return err;
}
#ifdef LFS_MIGRATE
int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
int err = LFS_LOCK(cfg);
if (err) {
return err;
}
LFS_TRACE("lfs_migrate(%p, %p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p, "
".read_size=%"PRIu32", .prog_size=%"PRIu32", "
".block_size=%"PRIu32", .block_count=%"PRIu32", "
".block_cycles=%"PRIu32", .cache_size=%"PRIu32", "
".lookahead_size=%"PRIu32", .read_buffer=%p, "
".prog_buffer=%p, .lookahead_buffer=%p, "
".name_max=%"PRIu32", .file_max=%"PRIu32", "
".attr_max=%"PRIu32"})",
(void*)lfs, (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,
cfg->block_cycles, cfg->cache_size, cfg->lookahead_size,
cfg->read_buffer, cfg->prog_buffer, cfg->lookahead_buffer,
cfg->name_max, cfg->file_max, cfg->attr_max);
err = lfs_rawmigrate(lfs, cfg);
LFS_TRACE("lfs_migrate -> %d", err);
LFS_UNLOCK(cfg);
return err;
}
#endif
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