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20b669a23d50bf191dc7225527487f9148122b8c
thirdparty-littlefs/lfs.c
Christopher Haster 20b669a23d Fixed issue with big-endian CTZ lists intertwined in commit logic 
Found while testing big-endian support. Basically, if littlefs is really
really unlucky, the block allocator could kick in while committing a
file's CTZ reference. If this happens, the block allocator will need to
traverse all CTZ skip-lists in memory, including the skip-list we're
committing. This means we can't convert the CTZ's endianness in place,
and need to make a copy on big-endian systems.

We rely on dead-code elimination from the compiler to make the
conditional behaviour for big-endian vs little-endian system a noop
determined by the lfs_tole32 intrinsic.
2018-10-16 20:53:25 -05:00

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/*
* The little filesystem
*
* Copyright (c) 2017 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "lfs.h"
#include "lfs_util.h"
/// Caching block device operations ///
static int lfs_cache_read(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, bool store,
lfs_block_t block, lfs_off_t off,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff);
while (size > 0) {
if (pcache && block == pcache->block &&
off >= pcache->off &&
off < pcache->off + pcache->size) {
// is already in pcache?
lfs_size_t diff = lfs_min(size, pcache->size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
if (block == rcache->block &&
off >= rcache->off &&
off < rcache->off + rcache->size) {
// is already in rcache?
lfs_size_t diff = lfs_min(size, rcache->size - (off-rcache->off));
if (pcache && block == pcache->block) {
diff = lfs_min(diff, pcache->off - off);
}
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
if (!store && off % lfs->cfg->read_size == 0 &&
size >= lfs->cfg->read_size) {
// bypass cache?
lfs_size_t diff = size - (size % lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
data += diff;
off += diff;
size -= diff;
continue;
}
// load to cache, first condition can no longer fail
LFS_ASSERT(block < lfs->cfg->block_count);
lfs_size_t nsize = store ? lfs->cfg->cache_size : lfs->cfg->prog_size;
rcache->block = block;
rcache->off = lfs_aligndown(off, nsize);
rcache->size = nsize;
int err = lfs->cfg->read(lfs->cfg, rcache->block,
rcache->off, rcache->buffer, nsize);
if (err) {
return err;
}
}
return 0;
}
static int lfs_cache_cmp(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
for (lfs_off_t i = 0; i < size; i++) {
uint8_t c;
int err = lfs_cache_read(lfs, pcache, rcache, true,
block, off+i, &c, 1);
if (err) {
return err;
}
if (c != data[i]) {
return false;
}
}
return true;
}
static int lfs_cache_crc(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
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 = lfs_cache_read(lfs, pcache, rcache, true,
block, off+i, &c, 1);
if (err) {
return err;
}
*crc = lfs_crc(*crc, &c, 1);
}
return 0;
}
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 = 0xffffffff;
}
static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
// zero to avoid information leak
memset(pcache->buffer, 0xff, lfs->cfg->prog_size);
pcache->block = 0xffffffff;
}
static int lfs_cache_flush(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
if (pcache->block != 0xffffffff) {
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);
if (err) {
return err;
}
if (validate) {
// check data on disk
lfs_cache_drop(lfs, rcache);
int res = lfs_cache_cmp(lfs, NULL, rcache, pcache->block,
pcache->off, pcache->buffer, diff);
if (res < 0) {
return res;
}
if (!res) {
return LFS_ERR_CORRUPT;
}
}
lfs_cache_zero(lfs, pcache);
}
return 0;
}
static int lfs_cache_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 != 0xffffffff);
LFS_ASSERT(off + size <= lfs->cfg->block_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 = off - pcache->off;
if (pcache->size == lfs->cfg->cache_size) {
// eagerly flush out pcache if we fill up
int err = lfs_cache_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 == 0xffffffff);
// 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;
}
/// General lfs block device operations ///
static int lfs_bd_read(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
return lfs_cache_read(lfs, &lfs->pcache, &lfs->rcache, true,
block, off, buffer, size);
}
static int lfs_bd_prog(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
return lfs_cache_prog(lfs, &lfs->pcache, &lfs->rcache, false,
block, off, buffer, size);
}
static int lfs_bd_cmp(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
return lfs_cache_cmp(lfs, NULL, &lfs->rcache, block, off, buffer, size);
}
static int lfs_bd_crc32(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, lfs_size_t size, uint32_t *crc) {
return lfs_cache_crc(lfs, NULL, &lfs->rcache, block, off, size, crc);
}
static int lfs_bd_erase(lfs_t *lfs, lfs_block_t block) {
LFS_ASSERT(block < lfs->cfg->block_count);
return lfs->cfg->erase(lfs->cfg, block);
}
static int lfs_bd_sync(lfs_t *lfs) {
lfs_cache_drop(lfs, &lfs->rcache);
int err = lfs_cache_flush(lfs, &lfs->pcache, &lfs->rcache, false);
if (err) {
return err;
}
return lfs->cfg->sync(lfs->cfg);
}
/// Internal operations predeclared here ///
static int lfs_fs_pred(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *pdir);
static int32_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *parent);
static int lfs_fs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], lfs_block_t newpair[2]);
static int lfs_fs_forceconsistency(lfs_t *lfs);
static int lfs_deinit(lfs_t *lfs);
/// Block allocator ///
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;
}
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;
}
return 0;
}
}
// check if we have looked at all blocks since last ack
if (lfs->free.ack == 0) {
LFS_WARN("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(lfs->cfg->lookahead, lfs->free.ack);
lfs->free.i = 0;
// find mask of free blocks from tree
memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
int err = lfs_fs_traverse(lfs, lfs_alloc_lookahead, lfs);
if (err) {
return err;
}
}
}
static void lfs_alloc_ack(lfs_t *lfs) {
lfs->free.ack = lfs->cfg->block_count;
}
/// Metadata pair and directory operations ///
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] == 0xffffffff || pair[1] == 0xffffffff;
}
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_sync(
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]);
}
static inline void lfs_pair_tole32(lfs_block_t pair[2]) {
pair[0] = lfs_tole32(pair[0]);
pair[1] = lfs_tole32(pair[1]);
}
static void lfs_ctz_fromle32(struct lfs_ctz *ctz) {
ctz->head = lfs_fromle32(ctz->head);
ctz->size = lfs_fromle32(ctz->size);
}
static void lfs_ctz_tole32(struct lfs_ctz *ctz) {
ctz->head = lfs_tole32(ctz->head);
ctz->size = lfs_tole32(ctz->size);
}
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->inline_max = lfs_fromle32(superblock->inline_max);
superblock->attr_max = lfs_fromle32(superblock->attr_max);
superblock->name_max = lfs_fromle32(superblock->name_max);
}
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->inline_max = lfs_tole32(superblock->inline_max);
superblock->attr_max = lfs_tole32(superblock->attr_max);
superblock->name_max = lfs_tole32(superblock->name_max);
}
/// Entry tag operations ///
#define LFS_MKTAG(type, id, size) \
(((uint32_t)(type) << 22) | ((uint32_t)(id) << 12) | (uint32_t)(size))
#define LFS_MKATTR(type, id, buffer, size, next) \
&(const lfs_mattr_t){LFS_MKTAG(type, id, size), (buffer), (next)}
static inline bool lfs_tag_isvalid(uint32_t tag) {
return !(tag & 0x80000000);
}
static inline bool lfs_tag_isuser(uint32_t tag) {
return (tag & 0x40000000);
}
static inline uint16_t lfs_tag_type(uint32_t tag) {
return (tag & 0x7fc00000) >> 22;
}
static inline uint16_t lfs_tag_subtype(uint32_t tag) {
return (tag & 0x7c000000) >> 22;
}
static inline uint16_t lfs_tag_id(uint32_t tag) {
return (tag & 0x003ff000) >> 12;
}
static inline lfs_size_t lfs_tag_size(uint32_t tag) {
return tag & 0x00000fff;
}
// operations on set of globals
static inline void lfs_global_xor(lfs_global_t *a, const lfs_global_t *b) {
for (int i = 0; i < sizeof(lfs_global_t)/4; i++) {
a->u32[i] ^= b->u32[i];
}
}
static inline bool lfs_global_iszero(const lfs_global_t *a) {
for (int i = 0; i < sizeof(lfs_global_t)/4; i++) {
if (a->u32[i] != 0) {
return false;
}
}
return true;
}
static inline void lfs_global_zero(lfs_global_t *a) {
lfs_global_xor(a, a);
}
static inline void lfs_global_fromle32(lfs_global_t *a) {
lfs_pair_fromle32(a->s.movepair);
a->s.moveid = lfs_fromle16(a->s.moveid);
}
static inline void lfs_global_tole32(lfs_global_t *a) {
lfs_pair_tole32(a->s.movepair);
a->s.moveid = lfs_tole16(a->s.moveid);
}
static inline void lfs_global_move(lfs_t *lfs,
const lfs_block_t pair[2], uint16_t id) {
lfs_global_t diff;
lfs_global_zero(&diff);
diff.s.movepair[0] ^= lfs->globals.s.movepair[0] ^ pair[0];
diff.s.movepair[1] ^= lfs->globals.s.movepair[1] ^ pair[1];
diff.s.moveid ^= lfs->globals.s.moveid ^ id;
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->locals, &diff);
lfs_global_tole32(&lfs->locals);
lfs_global_xor(&lfs->globals, &diff);
}
static inline void lfs_global_deorphaned(lfs_t *lfs, bool deorphaned) {
lfs->locals.s.deorphaned ^= lfs->globals.s.deorphaned ^ deorphaned;
lfs->globals.s.deorphaned ^= lfs->globals.s.deorphaned ^ deorphaned;
}
// commit logic
struct lfs_commit {
lfs_block_t block;
lfs_off_t off;
uint32_t ptag;
uint32_t crc;
lfs_off_t begin;
lfs_off_t end;
};
struct lfs_diskoff {
lfs_block_t block;
lfs_off_t off;
};
static int32_t lfs_commit_get(lfs_t *lfs, lfs_block_t block, lfs_off_t off,
uint32_t tag, uint32_t getmask, uint32_t gettag, int32_t getdiff,
void *buffer, bool stopatcommit) {
// iterate over dir block backwards (for faster lookups)
while (off >= 2*sizeof(tag)+lfs_tag_size(tag)) {
off -= sizeof(tag)+lfs_tag_size(tag);
if (lfs_tag_type(tag) == LFS_TYPE_CRC && stopatcommit) {
break;
} else if (lfs_tag_type(tag) == LFS_TYPE_DELETE) {
if (lfs_tag_id(tag) <= lfs_tag_id(gettag + getdiff)) {
getdiff += LFS_MKTAG(0, 1, 0);
}
} else if ((tag & getmask) == ((gettag + getdiff) & getmask)) {
if (buffer) {
lfs_size_t diff = lfs_min(
lfs_tag_size(gettag), lfs_tag_size(tag));
int err = lfs_bd_read(lfs, block,
off+sizeof(tag), buffer, diff);
if (err) {
return err;
}
memset((uint8_t*)buffer + diff, 0,
lfs_tag_size(gettag) - diff);
}
return tag - getdiff;
}
uint32_t ntag;
int err = lfs_bd_read(lfs, block, off, &ntag, sizeof(ntag));
if (err) {
return err;
}
tag ^= lfs_fromle32(ntag);
}
return LFS_ERR_NOENT;
}
static int lfs_commit_attrs(lfs_t *lfs, struct lfs_commit *commit,
uint16_t id, const struct lfs_attr *attrs);
static int lfs_commit_move(lfs_t *lfs, struct lfs_commit *commit,
uint16_t fromid, uint16_t toid,
const lfs_mdir_t *dir, const lfs_mattr_t *attrs);
static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
uint32_t tag, const void *buffer) {
if (lfs_tag_subtype(tag) == LFS_FROM_MOVE) {
// special case for moves
return lfs_commit_move(lfs, commit,
lfs_tag_size(tag), lfs_tag_id(tag),
buffer, NULL);
} else if (lfs_tag_subtype(tag) == LFS_FROM_ATTRS) {
// special case for custom attributes
return lfs_commit_attrs(lfs, commit,
lfs_tag_id(tag), buffer);
}
// check if we fit
lfs_size_t size = lfs_tag_size(tag);
if (commit->off + sizeof(tag)+size > commit->end) {
return LFS_ERR_NOSPC;
}
// write out tag
uint32_t ntag = lfs_tole32((tag & 0x7fffffff) ^ commit->ptag);
commit->crc = lfs_crc(commit->crc, &ntag, sizeof(ntag));
int err = lfs_bd_prog(lfs, commit->block, commit->off,
&ntag, sizeof(ntag));
if (err) {
return err;
}
commit->off += sizeof(ntag);
if (!(tag & 0x80000000)) {
// from memory
commit->crc = lfs_crc(commit->crc, buffer, size);
err = lfs_bd_prog(lfs, commit->block, commit->off, buffer, size);
if (err) {
return err;
}
} else {
// from disk
const struct lfs_diskoff *disk = buffer;
for (lfs_off_t i = 0; i < size; i++) {
// rely on caching to make this efficient
uint8_t dat;
err = lfs_bd_read(lfs, disk->block, disk->off+i, &dat, 1);
if (err) {
return err;
}
commit->crc = lfs_crc(commit->crc, &dat, 1);
err = lfs_bd_prog(lfs, commit->block, commit->off+i, &dat, 1);
if (err) {
return err;
}
}
}
commit->off += size;
commit->ptag = tag & 0x7fffffff;
return 0;
}
static int lfs_commit_attrs(lfs_t *lfs, struct lfs_commit *commit,
uint16_t id, const struct lfs_attr *attrs) {
for (const struct lfs_attr *a = attrs; a; a = a->next) {
int err = lfs_commit_attr(lfs, commit,
LFS_MKTAG(0x100 | a->type, id, a->size), a->buffer);
if (err) {
return err;
}
}
return 0;
}
static int lfs_commit_move(lfs_t *lfs, struct lfs_commit *commit,
uint16_t fromid, uint16_t toid,
const lfs_mdir_t *dir, const lfs_mattr_t *attrs) {
// iterate through list and commits, only committing unique entries
lfs_off_t off = dir->off;
uint32_t ntag = dir->etag;
while (attrs || off > sizeof(uint32_t)) {
struct lfs_diskoff disk;
uint32_t tag;
const void *buffer;
if (attrs) {
tag = attrs->tag;
buffer = attrs->buffer;
attrs = attrs->next;
} else {
LFS_ASSERT(off > sizeof(ntag)+lfs_tag_size(ntag));
off -= sizeof(ntag)+lfs_tag_size(ntag);
tag = ntag;
buffer = &disk;
disk.block = dir->pair[0];
disk.off = off + sizeof(tag);
int err = lfs_bd_read(lfs, dir->pair[0], off, &ntag, sizeof(ntag));
if (err) {
return err;
}
ntag = lfs_fromle32(ntag);
ntag ^= tag;
tag |= 0x80000000;
}
if (lfs_tag_type(tag) == LFS_TYPE_DELETE &&
lfs_tag_id(tag) <= fromid) {
// something was deleted, we need to move around it
fromid += 1;
} else if (lfs_tag_id(tag) != fromid) {
// ignore non-matching ids
} else {
// check if type has already been committed
int32_t res = lfs_commit_get(lfs, commit->block,
commit->off, commit->ptag,
lfs_tag_isuser(tag) ? 0x7ffff000 : 0x7c3ff000,
(tag & 0x7fc00000) | LFS_MKTAG(0, toid, 0),
0, NULL, true);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
if (res == LFS_ERR_NOENT) {
// update id and commit, as we are currently unique
int err = lfs_commit_attr(lfs, commit,
(tag & 0xffc00fff) | LFS_MKTAG(0, toid, 0),
buffer);
if (err) {
return err;
}
}
}
}
return 0;
}
static int lfs_commit_globals(lfs_t *lfs, struct lfs_commit *commit,
lfs_global_t *locals) {
if (lfs_global_iszero(&lfs->locals)) {
return 0;
}
lfs_global_xor(locals, &lfs->locals);
int err = lfs_commit_attr(lfs, commit,
LFS_MKTAG(LFS_TYPE_GLOBALS + locals->s.deorphaned, 0x3ff, 10),
locals);
lfs_global_xor(locals, &lfs->locals);
return err;
}
static int lfs_commit_crc(lfs_t *lfs, struct lfs_commit *commit) {
// align to program units
lfs_off_t off = lfs_alignup(commit->off + 2*sizeof(uint32_t),
lfs->cfg->prog_size);
// read erased state from next program unit
uint32_t tag;
int err = lfs_bd_read(lfs, commit->block, off, &tag, sizeof(tag));
if (err) {
return err;
}
// build crc tag
tag = lfs_fromle32(tag);
tag = (0x80000000 & ~tag) |
LFS_MKTAG(LFS_TYPE_CRC, 0x3ff,
off - (commit->off+sizeof(uint32_t)));
// write out crc
uint32_t footer[2];
footer[0] = lfs_tole32(tag ^ commit->ptag);
commit->crc = lfs_crc(commit->crc, &footer[0], sizeof(footer[0]));
footer[1] = lfs_tole32(commit->crc);
err = lfs_bd_prog(lfs, commit->block, commit->off, footer, sizeof(footer));
if (err) {
return err;
}
commit->off += sizeof(tag)+lfs_tag_size(tag);
commit->ptag = tag;
// flush buffers
err = lfs_bd_sync(lfs);
if (err) {
return err;
}
// successful commit, check checksum to make sure
uint32_t crc = 0xffffffff;
err = lfs_bd_crc32(lfs, commit->block, commit->begin,
commit->off-lfs_tag_size(tag)-commit->begin, &crc);
if (err) {
return err;
}
if (crc != commit->crc) {
return LFS_ERR_CORRUPT;
}
return 0;
}
// internal dir operations
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;
}
}
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->rev, 4);
dir->rev = lfs_fromle32(dir->rev);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// set defaults
dir->off = sizeof(dir->rev);
dir->etag = 0;
dir->count = 0;
dir->tail[0] = 0xffffffff;
dir->tail[1] = 0xffffffff;
dir->erased = false;
dir->split = false;
lfs_global_zero(&dir->locals);
// don't write out yet, let caller take care of that
return 0;
}
static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2],
uint32_t findmask, uint32_t findtag, const void *findbuffer) {
dir->pair[0] = pair[0];
dir->pair[1] = pair[1];
int32_t foundtag = LFS_ERR_NOENT;
// find the block with the most recent revision
uint32_t rev[2];
for (int i = 0; i < 2; i++) {
int err = lfs_cache_read(lfs, &lfs->pcache, &lfs->rcache, false,
dir->pair[i], 0, &rev[i], sizeof(rev[i]));
rev[i] = lfs_fromle32(rev[i]);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err == LFS_ERR_CORRUPT) {
rev[i] = rev[(i+1)%2] - 1;
}
}
if (lfs_scmp(rev[1], rev[0]) > 0) {
lfs_pair_swap(dir->pair);
lfs_pair_swap(rev);
}
// load blocks and check crc
for (int i = 0; i < 2; i++) {
lfs_off_t off = sizeof(dir->rev);
uint32_t ptag = 0;
uint32_t crc = 0xffffffff;
dir->rev = lfs_tole32(rev[0]);
crc = lfs_crc(crc, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
dir->off = 0;
uint32_t tempfoundtag = foundtag;
uint16_t tempcount = 0;
lfs_block_t temptail[2] = {0xffffffff, 0xffffffff};
bool tempsplit = false;
lfs_global_t templocals;
lfs_global_zero(&templocals);
while (true) {
// extract next tag
uint32_t tag;
int err = lfs_bd_read(lfs, dir->pair[0],
off, &tag, sizeof(tag));
if (err) {
if (err == LFS_ERR_CORRUPT) {
// can't continue?
dir->erased = false;
break;
}
return err;
}
crc = lfs_crc(crc, &tag, sizeof(tag));
tag = lfs_fromle32(tag) ^ ptag;
// next commit not yet programmed
if (lfs_tag_type(ptag) == LFS_TYPE_CRC && !lfs_tag_isvalid(tag)) {
dir->erased = true;
break;
}
// check we're in valid range
if (off + sizeof(tag)+lfs_tag_size(tag) > lfs->cfg->block_size) {
dir->erased = false;
break;
}
if (lfs_tag_type(tag) == LFS_TYPE_CRC) {
// check the crc attr
uint32_t dcrc;
err = lfs_bd_read(lfs, dir->pair[0],
off+sizeof(tag), &dcrc, sizeof(dcrc));
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return err;
}
dcrc = lfs_fromle32(dcrc);
if (crc != dcrc) {
dir->erased = false;
break;
}
foundtag = tempfoundtag;
dir->off = off + sizeof(tag)+lfs_tag_size(tag);
dir->etag = tag;
dir->count = tempcount;
dir->tail[0] = temptail[0];
dir->tail[1] = temptail[1];
dir->split = tempsplit;
dir->locals = templocals;
crc = 0xffffffff;
} else {
err = lfs_bd_crc32(lfs, dir->pair[0],
off+sizeof(tag), lfs_tag_size(tag), &crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
}
if (lfs_tag_id(tag) < 0x3ff && lfs_tag_id(tag) >= tempcount) {
tempcount = lfs_tag_id(tag)+1;
}
if (lfs_tag_subtype(tag) == LFS_TYPE_TAIL) {
tempsplit = (lfs_tag_type(tag) & 1);
err = lfs_bd_read(lfs, dir->pair[0], off+sizeof(tag),
temptail, sizeof(temptail));
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
}
lfs_pair_fromle32(temptail);
} else if (lfs_tag_subtype(tag) == LFS_TYPE_GLOBALS) {
templocals.s.deorphaned = (lfs_tag_type(tag) & 1);
err = lfs_bd_read(lfs, dir->pair[0], off+sizeof(tag),
&templocals, 10);
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
}
} else if (lfs_tag_subtype(tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(tempcount > 0);
tempcount -= 1;
if (lfs_tag_id(tag) == lfs_tag_id(tempfoundtag)) {
tempfoundtag = LFS_ERR_NOENT;
} else if (lfs_tag_isvalid(tempfoundtag) &&
lfs_tag_id(tag) < lfs_tag_id(tempfoundtag)) {
tempfoundtag -= LFS_MKTAG(0, 1, 0);
}
} else if ((tag & findmask) == (findtag & findmask)) {
int res = lfs_bd_cmp(lfs, dir->pair[0], off+sizeof(tag),
findbuffer, lfs_tag_size(findtag));
if (res < 0) {
if (res == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return res;
}
if (res) {
// found a match
tempfoundtag = tag;
}
}
}
ptag = tag;
off += sizeof(tag)+lfs_tag_size(tag);
}
// consider what we have good enough
if (dir->off > 0) {
// synthetic move
if (lfs_pair_cmp(dir->pair, lfs->globals.s.movepair) == 0) {
if (lfs->globals.s.moveid == lfs_tag_id(foundtag)) {
foundtag = LFS_ERR_NOENT;
} else if (lfs_tag_isvalid(foundtag) &&
lfs->globals.s.moveid < lfs_tag_id(foundtag)) {
foundtag -= LFS_MKTAG(0, 1, 0);
}
}
return foundtag;
}
// failed, try the other crc?
lfs_pair_swap(dir->pair);
lfs_pair_swap(rev);
}
LFS_ERROR("Corrupted dir pair at %"PRIu32" %"PRIu32,
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]) {
int32_t res = lfs_dir_fetchmatch(lfs, dir, pair,
0xffffffff, 0xffffffff, NULL);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
return 0;
}
static int32_t lfs_dir_find(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2], bool fs,
uint32_t findmask, uint32_t findtag, const void *findbuffer) {
dir->split = true;
dir->tail[0] = pair[0];
dir->tail[1] = pair[1];
while ((dir->split || fs) && !lfs_pair_isnull(dir->tail)) {
int32_t tag = lfs_dir_fetchmatch(lfs, dir, dir->tail,
findmask, findtag, findbuffer);
if (tag != LFS_ERR_NOENT) {
return tag;
}
}
return LFS_ERR_NOENT;
}
static int32_t lfs_dir_get(lfs_t *lfs, lfs_mdir_t *dir,
uint32_t getmask, uint32_t gettag, void *buffer) {
int32_t getdiff = 0;
if (lfs_pair_cmp(dir->pair, lfs->globals.s.movepair) == 0 &&
lfs_tag_id(gettag) <= lfs->globals.s.moveid) {
// synthetic moves
getdiff = LFS_MKTAG(0, 1, 0);
}
return lfs_commit_get(lfs, dir->pair[0], dir->off, dir->etag,
getmask, gettag, getdiff, buffer, false);
}
static int lfs_dir_compact(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_mattr_t *attrs,
lfs_mdir_t *source, uint16_t begin, uint16_t end) {
// save some state in case block is bad
const lfs_block_t oldpair[2] = {dir->pair[1], dir->pair[0]};
int16_t ack;
bool expanding = false;
bool relocated = false;
// There's nothing special about our global delta, so feed it back
// into the global global delta
lfs_global_xor(&lfs->locals, &dir->locals);
lfs_global_zero(&dir->locals);
// increment revision count
dir->rev += 1;
if (lfs_pair_cmp(dir->pair, (const lfs_block_t[2]){0, 1}) == 0 &&
dir->rev % 16 == 0) {
// we're writing too much to the superblock, should we expand?
lfs_ssize_t res = lfs_fs_size(lfs);
if (res < 0) {
return res;
}
// do we have enough space to expand?
if (res < lfs->cfg->block_count/2) {
expanding = (lfs_pair_cmp(dir->pair, lfs->root) != 0);
ack = 0;
goto split;
}
}
while (true) {
// last complete id
ack = -1;
dir->count = end - begin;
if (true) {
// 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
uint32_t crc = 0xffffffff;
uint32_t rev = lfs_tole32(dir->rev);
crc = lfs_crc(crc, &rev, sizeof(rev));
err = lfs_bd_prog(lfs, dir->pair[1], 0, &rev, sizeof(rev));
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// setup compaction
struct lfs_commit commit = {
.block = dir->pair[1],
.off = sizeof(dir->rev),
.crc = crc,
.ptag = 0,
// space is complicated, we need room for tail, crc, globals,
// and we cap at half a block to give room for metadata updates
.begin = 0,
.end = lfs_min(
lfs_alignup(lfs->cfg->block_size/2, lfs->cfg->prog_size),
lfs->cfg->block_size - 34),
};
// commit with a move
for (uint16_t id = begin; id < end; id++) {
err = lfs_commit_move(lfs, &commit,
id, id - begin, source, attrs);
if (err) {
if (err == LFS_ERR_NOSPC) {
goto split;
} else if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
ack = id;
}
// reopen reserved space at the end
commit.end = lfs->cfg->block_size - 8;
if (!relocated) {
err = lfs_commit_globals(lfs, &commit, &dir->locals);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
if (!lfs_pair_isnull(dir->tail)) {
// commit tail, which may be new after last size check
lfs_pair_tole32(dir->tail);
err = lfs_commit_attr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_TAIL + dir->split,
0x3ff, sizeof(dir->tail)), dir->tail);
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
err = lfs_commit_crc(lfs, &commit);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// successful compaction, swap dir pair to indicate most recent
lfs_pair_swap(dir->pair);
dir->off = commit.off;
dir->etag = commit.ptag;
dir->erased = true;
}
break;
split:
// commit no longer fits, need to split dir,
// drop caches and create tail
lfs_cache_drop(lfs, &lfs->pcache);
if (ack == -1) {
// If we can't fit in this block, we won't fit in next block
return LFS_ERR_NOSPC;
}
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];
err = lfs_dir_compact(lfs, &tail, attrs, source, ack+1-expanding, end);
if (err) {
return err;
}
end = ack+1;
dir->tail[0] = tail.pair[0];
dir->tail[1] = tail.pair[1];
dir->split = true;
continue;
relocate:
//commit was corrupted
LFS_DEBUG("Bad block at %"PRIu32,
dir->pair[1]);
// drop caches and prepare to relocate block
relocated = true;
lfs_cache_drop(lfs, &lfs->pcache);
// can't relocate superblock, filesystem is now frozen
if (lfs_pair_cmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
LFS_WARN("Superblock %"PRIu32" has become unwritable", oldpair[1]);
return LFS_ERR_CORRUPT;
}
// relocate half of pair
err = lfs_alloc(lfs, &dir->pair[1]);
if (err) {
return err;
}
continue;
}
if (!relocated) {
// successful commit, update globals
lfs_global_xor(&dir->locals, &lfs->locals);
lfs_global_zero(&lfs->locals);
} else {
// update references if we relocated
LFS_DEBUG("Relocating %"PRIu32" %"PRIu32" to %"PRIu32" %"PRIu32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
int err = lfs_fs_relocate(lfs, oldpair, dir->pair);
if (err) {
return err;
}
}
return 0;
}
static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
const lfs_mattr_t *attrs) {
lfs_mattr_t cancelattr;
lfs_global_t canceldiff;
lfs_global_zero(&canceldiff);
if (lfs_pair_cmp(dir->pair, lfs->globals.s.movepair) == 0) {
// Wait, we have the move? Just cancel this out here
// We need to, or else the move can become outdated
canceldiff.s.movepair[0] ^= lfs->globals.s.movepair[0] ^ 0xffffffff;
canceldiff.s.movepair[1] ^= lfs->globals.s.movepair[1] ^ 0xffffffff;
canceldiff.s.moveid ^= lfs->globals.s.moveid ^ 0x3ff;
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->locals, &canceldiff);
lfs_global_tole32(&lfs->locals);
cancelattr.tag = LFS_MKTAG(LFS_TYPE_DELETE, lfs->globals.s.moveid, 0);
cancelattr.next = attrs;
attrs = &cancelattr;
}
// calculate new directory size
uint32_t deletetag = 0xffffffff;
for (const lfs_mattr_t *a = attrs; a; a = a->next) {
if (lfs_tag_id(a->tag) < 0x3ff && lfs_tag_id(a->tag) >= dir->count) {
dir->count = lfs_tag_id(a->tag)+1;
}
if (lfs_tag_type(a->tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(dir->count > 0);
dir->count -= 1;
deletetag = a->tag;
if (dir->count == 0) {
// should we actually drop the directory block?
lfs_mdir_t 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) {
// steal tail and global state
pdir.split = dir->split;
pdir.tail[0] = dir->tail[0];
pdir.tail[1] = dir->tail[1];
lfs_global_xor(&lfs->locals, &dir->locals);
return lfs_dir_commit(lfs, &pdir,
LFS_MKATTR(LFS_TYPE_TAIL + pdir.split, 0x3ff,
pdir.tail, sizeof(pdir.tail),
NULL));
}
}
}
}
if (dir->erased) {
// try to commit
struct lfs_commit commit = {
.block = dir->pair[0],
.off = dir->off,
.crc = 0xffffffff,
.ptag = dir->etag,
.begin = dir->off,
.end = lfs->cfg->block_size - 8,
};
for (const lfs_mattr_t *a = attrs; a; a = a->next) {
if (lfs_tag_type(a->tag) != LFS_TYPE_DELETE) {
lfs_pair_tole32(dir->tail);
int err = lfs_commit_attr(lfs, &commit, a->tag, a->buffer);
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
}
}
if (lfs_tag_isvalid(deletetag)) {
// special case for deletes, since order matters
int err = lfs_commit_attr(lfs, &commit, deletetag, NULL);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
}
int err = lfs_commit_globals(lfs, &commit, &dir->locals);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
err = lfs_commit_crc(lfs, &commit);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
// successful commit, update dir
dir->off = commit.off;
dir->etag = commit.ptag;
// successful commit, update globals
lfs_global_xor(&dir->locals, &lfs->locals);
lfs_global_zero(&lfs->locals);
} else {
compact:
// fall back to compaction
lfs_cache_drop(lfs, &lfs->pcache);
int err = lfs_dir_compact(lfs, dir, attrs, dir, 0, dir->count);
if (err) {
return err;
}
}
// update globals that are affected
lfs_global_xor(&lfs->globals, &canceldiff);
// update any directories that are affected
lfs_mdir_t copy = *dir;
// two passes, once for things that aren't us, and one
// for things that are
for (lfs_mlist_t *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(d->m.pair, copy.pair) == 0) {
d->m = *dir;
if (d->id == lfs_tag_id(deletetag)) {
d->m.pair[0] = 0xffffffff;
d->m.pair[1] = 0xffffffff;
} else if (d->id > lfs_tag_id(deletetag)) {
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 0;
}
static int32_t lfs_dir_lookup(lfs_t *lfs, lfs_mdir_t *dir, const char **path) {
// we reduce path to a single name if we can find it
const char *name = *path;
*path = NULL;
// default to root dir
int32_t tag = LFS_MKTAG(LFS_TYPE_DIR, 0x3ff, 0);
lfs_block_t pair[2] = {lfs->root[0], 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 if path is only a name
if (strchr(name, '/') == NULL) {
*path = name;
}
// only continue if we hit a directory
if (lfs_tag_type(tag) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
// grab the entry data
if (lfs_tag_id(tag) != 0x3ff) {
int32_t res = lfs_dir_get(lfs, dir, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
}
// find entry matching name
tag = lfs_dir_find(lfs, dir, pair, false, 0x7c000fff,
LFS_MKTAG(LFS_TYPE_NAME, 0, namelen), name);
if (tag < 0) {
return tag;
}
// to next name
name += namelen;
}
}
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;
}
int32_t tag = lfs_dir_get(lfs, dir, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_NAME, id, lfs->name_max+1), info->name);
if (tag < 0) {
return tag;
}
info->type = lfs_tag_type(tag);
struct lfs_ctz ctz;
tag = lfs_dir_get(lfs, dir, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_STRUCT, id, sizeof(ctz)), &ctz);
if (tag < 0) {
return tag;
}
lfs_ctz_fromle32(&ctz);
if (lfs_tag_type(tag) == LFS_TYPE_CTZSTRUCT) {
info->size = ctz.size;
} else if (lfs_tag_type(tag) == LFS_TYPE_INLINESTRUCT) {
info->size = lfs_tag_size(tag);
}
return 0;
}
/// Top level directory operations ///
int lfs_mkdir(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;
int32_t res = lfs_dir_lookup(lfs, &cwd, &path);
if (!(res == LFS_ERR_NOENT && path)) {
return (res < 0) ? res : 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;
}
dir.tail[0] = cwd.tail[0];
dir.tail[1] = cwd.tail[1];
err = lfs_dir_commit(lfs, &dir, NULL);
if (err) {
return err;
}
// get next slot and commit
uint16_t id = cwd.count;
cwd.tail[0] = dir.pair[0];
cwd.tail[1] = dir.pair[1];
lfs_pair_tole32(dir.pair);
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_DIR, id, path, nlen,
LFS_MKATTR(LFS_TYPE_DIRSTRUCT, id, dir.pair, sizeof(dir.pair),
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x3ff, cwd.tail, sizeof(cwd.tail),
NULL))));
lfs_pair_fromle32(dir.pair);
if (err) {
return err;
}
return 0;
}
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
int32_t tag = lfs_dir_lookup(lfs, &dir->m, &path);
if (tag < 0) {
return tag;
}
if (lfs_tag_type(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
int32_t res = lfs_dir_get(lfs, &dir->m, 0x7c3ff000,
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;
dir->next = (lfs_dir_t*)lfs->mlist;
lfs->mlist = (lfs_mlist_t*)dir;
return 0;
}
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
// remove from list of mdirs
for (lfs_mlist_t **p = &lfs->mlist; *p; p = &(*p)->next) {
if (*p == (lfs_mlist_t*)dir) {
*p = (*p)->next;
break;
}
}
return 0;
}
int lfs_dir_read(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 1;
} else if (dir->pos == 1) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, "..");
dir->pos += 1;
return 1;
}
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;
}
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
// simply walk from head dir
int err = lfs_dir_rewind(lfs, dir);
if (err) {
return err;
}
// first two for ./..
dir->pos = lfs_min(2, off);
off -= dir->pos;
while (off != 0) {
dir->id = lfs_min(dir->m.count, off);
dir->pos += dir->id;
off -= dir->id;
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;
}
}
}
return 0;
}
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir) {
(void)lfs;
return dir->pos;
}
int lfs_dir_rewind(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->m.pair[0] = dir->head[0];
dir->m.pair[1] = dir->head[1];
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 = 0xffffffff;
*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_cache_read(lfs, pcache, rcache, false,
head, 4*skip, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
current -= 1 << skip;
}
*block = head;
*off = pos;
return 0;
}
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;
}
LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
if (true) {
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;
}
size -= 1;
lfs_off_t index = lfs_ctz_index(lfs, &size);
size += 1;
// just copy out the last block if it is incomplete
if (size != lfs->cfg->block_size) {
for (lfs_off_t i = 0; i < size; i++) {
uint8_t data;
err = lfs_cache_read(lfs, NULL, rcache, true,
head, i, &data, 1);
if (err) {
return err;
}
err = lfs_cache_prog(lfs, pcache, rcache, true,
nblock, i, &data, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
*block = nblock;
*off = size;
return 0;
}
// append block
index += 1;
lfs_size_t skips = lfs_ctz(index) + 1;
for (lfs_off_t i = 0; i < skips; i++) {
head = lfs_tole32(head);
err = lfs_cache_prog(lfs, pcache, rcache, true,
nblock, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (i != skips-1) {
err = lfs_cache_read(lfs, NULL, rcache, false,
head, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
}
*block = nblock;
*off = 4*skips;
return 0;
}
relocate:
LFS_DEBUG("Bad block at %"PRIu32, nblock);
// just clear cache and try a new block
lfs_cache_drop(lfs, pcache);
}
}
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_cache_read(lfs, pcache, rcache, false,
head, 0, &heads, count*4);
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 ///
int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags,
const struct lfs_file_config *cfg) {
// deorphan if we haven't yet, needed at most once after poweron
if ((flags & 3) != LFS_O_RDONLY) {
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
}
// setup simple file details
int err = 0;
file->cfg = cfg;
file->flags = flags;
file->pos = 0;
file->cache.buffer = NULL;
// allocate entry for file if it doesn't exist
int32_t tag = lfs_dir_lookup(lfs, &file->m, &path);
if (tag < 0 && !(tag == LFS_ERR_NOENT && path)) {
err = tag;
goto cleanup;
}
// get id, add to list of mdirs to catch update changes
file->id = lfs_tag_id(tag);
file->type = LFS_TYPE_REG;
file->next = (lfs_file_t*)lfs->mlist;
lfs->mlist = (lfs_mlist_t*)file;
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
file->id = file->m.count;
err = lfs_dir_commit(lfs, &file->m,
LFS_MKATTR(LFS_TYPE_REG, file->id, path, nlen,
LFS_MKATTR(LFS_TYPE_INLINESTRUCT, file->id, NULL, 0,
NULL)));
if (err) {
err = LFS_ERR_NAMETOOLONG;
goto cleanup;
}
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, 0);
} else if (flags & LFS_O_EXCL) {
err = LFS_ERR_EXIST;
goto cleanup;
} else if (lfs_tag_type(tag) != LFS_TYPE_REG) {
err = LFS_ERR_ISDIR;
goto cleanup;
} else if (flags & LFS_O_TRUNC) {
// truncate if requested
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0);
file->flags |= LFS_F_DIRTY;
} else {
// try to load what's on disk, if it's inlined we'll fix it later
tag = lfs_dir_get(lfs, &file->m, 0x7c3ff000,
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 (const struct lfs_attr *a = file->cfg->attrs; a; a = a->next) {
if ((file->flags & 3) != LFS_O_WRONLY) {
int32_t res = lfs_dir_get(lfs, &file->m, 0x7ffff000,
LFS_MKTAG(0x100 | a->type, file->id, a->size), a->buffer);
if (res < 0 && res != LFS_ERR_NOENT) {
err = res;
goto cleanup;
}
}
if ((file->flags & 3) != LFS_O_RDONLY) {
if (a->size > lfs->attr_max) {
err = LFS_ERR_NOSPC;
goto cleanup;
}
file->flags |= LFS_F_DIRTY;
}
}
// 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_type(tag) == LFS_TYPE_INLINESTRUCT) {
// load inline files
file->ctz.head = 0xfffffffe;
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) {
int32_t res = lfs_dir_get(lfs, &file->m, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_STRUCT, file->id, file->ctz.size),
file->cache.buffer);
if (res < 0) {
err = res;
goto cleanup;
}
}
}
return 0;
cleanup:
// clean up lingering resources
file->flags |= LFS_F_ERRED;
lfs_file_close(lfs, file);
return err;
}
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags) {
static const struct lfs_file_config defaults = {0};
return lfs_file_opencfg(lfs, file, path, flags, &defaults);
}
int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_sync(lfs, file);
// remove from list of mdirs
for (lfs_mlist_t **p = &lfs->mlist; *p; p = &(*p)->next) {
if (*p == (lfs_mlist_t*)file) {
*p = (*p)->next;
break;
}
}
// clean up memory
if (file->cfg->buffer) {
lfs_free(file->cache.buffer);
}
return err;
}
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;
err = lfs_cache_read(lfs, &file->cache, &lfs->rcache, true,
file->block, i, &data, 1);
if (err) {
return err;
}
err = lfs_cache_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;
return 0;
relocate:
continue;
}
}
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
if (file->flags & LFS_F_READING) {
file->flags &= ~LFS_F_READING;
}
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_read(lfs, &orig, &data, 1);
if (res < 0) {
return res;
}
res = lfs_file_write(lfs, file, &data, 1);
if (res < 0) {
return res;
}
// keep our reference to the rcache in sync
if (lfs->rcache.block != 0xffffffff) {
lfs_cache_drop(lfs, &orig.cache);
lfs_cache_drop(lfs, &lfs->rcache);
}
}
// write out what we have
while (true) {
int err = lfs_cache_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 %"PRIu32, file->block);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
}
} else {
file->ctz.size = 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;
}
return 0;
}
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
while (true) {
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
if ((file->flags & LFS_F_DIRTY) &&
!(file->flags & LFS_F_ERRED) &&
!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 if (lfs_tole32(0x11223344) == 0x11223344) {
// 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_MKATTR(type, file->id, buffer, size,
LFS_MKATTR(LFS_FROM_ATTRS, file->id, file->cfg->attrs, 0,
NULL)));
if (err) {
if (err == LFS_ERR_NOSPC && (file->flags & LFS_F_INLINE)) {
goto relocate;
}
return err;
}
file->flags &= ~LFS_F_DIRTY;
}
return 0;
relocate:
// inline file doesn't fit anymore
file->block = 0xfffffffe;
file->off = file->pos;
lfs_alloc_ack(lfs);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
file->flags &= ~LFS_F_INLINE;
file->flags |= LFS_F_WRITING;
}
}
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_WRONLY) {
return LFS_ERR_BADF;
}
if (file->flags & LFS_F_WRITING) {
// flush out any writes
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
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 = 0xfffffffe;
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);
int err = lfs_cache_read(lfs, NULL, &file->cache, true,
file->block, file->off, data, diff);
if (err) {
return err;
}
file->pos += diff;
file->off += diff;
data += diff;
nsize -= diff;
}
return size;
}
lfs_ssize_t lfs_file_write(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 & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
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->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_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
}
if ((file->flags & LFS_F_INLINE) &&
file->pos + nsize >= lfs->inline_max) {
// inline file doesn't fit anymore
file->block = 0xfffffffe;
file->off = file->pos;
lfs_alloc_ack(lfs);
int err = lfs_file_relocate(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
file->flags &= ~LFS_F_INLINE;
file->flags |= LFS_F_WRITING;
}
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 = 0xfffffffe;
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_cache_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);
}
file->flags &= ~LFS_F_ERRED;
return size;
}
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
// write out everything beforehand, may be noop if rdonly
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// update pos
if (whence == LFS_SEEK_SET) {
file->pos = off;
} else if (whence == LFS_SEEK_CUR) {
if (off < 0 && (lfs_off_t)-off > file->pos) {
return LFS_ERR_INVAL;
}
file->pos = file->pos + off;
} else if (whence == LFS_SEEK_END) {
if (off < 0 && (lfs_off_t)-off > file->ctz.size) {
return LFS_ERR_INVAL;
}
file->pos = file->ctz.size + off;
}
return file->pos;
}
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
lfs_off_t oldsize = lfs_file_size(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->ctz.head, &(lfs_off_t){0});
if (err) {
return err;
}
file->ctz.size = size;
file->flags |= LFS_F_DIRTY;
} else if (size > oldsize) {
lfs_off_t pos = file->pos;
// flush+seek if not already at end
if (file->pos != oldsize) {
int err = lfs_file_seek(lfs, file, 0, LFS_SEEK_END);
if (err < 0) {
return err;
}
}
// fill with zeros
while (file->pos < size) {
lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
// restore pos
int err = lfs_file_seek(lfs, file, pos, LFS_SEEK_SET);
if (err < 0) {
return err;
}
}
return 0;
}
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
return file->pos;
}
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file) {
lfs_soff_t res = lfs_file_seek(lfs, file, 0, LFS_SEEK_SET);
if (res < 0) {
return res;
}
return 0;
}
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
if (file->flags & LFS_F_WRITING) {
return lfs_max(file->pos, file->ctz.size);
} else {
return file->ctz.size;
}
}
/// General fs operations ///
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
lfs_mdir_t cwd;
int32_t tag = lfs_dir_lookup(lfs, &cwd, &path);
if (tag < 0) {
return tag;
}
return lfs_dir_getinfo(lfs, &cwd, lfs_tag_id(tag), info);
}
int lfs_remove(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;
err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
int32_t tag = lfs_dir_lookup(lfs, &cwd, &path);
if (tag < 0) {
return tag;
}
lfs_mdir_t dir;
if (lfs_tag_type(tag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t pair[2];
int32_t res = lfs_dir_get(lfs, &cwd, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
err = lfs_dir_fetch(lfs, &dir, pair);
if (err) {
return err;
}
if (dir.count > 0 || dir.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
lfs_global_deorphaned(lfs, false);
}
// delete the entry
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_DELETE, lfs_tag_id(tag), NULL, 0,
NULL));
if (err) {
return err;
}
if (lfs_tag_type(tag) == LFS_TYPE_DIR) {
err = lfs_fs_pred(lfs, dir.pair, &cwd);
if (err) {
return err;
}
// fix orphan
lfs_global_deorphaned(lfs, true);
// steal state
cwd.tail[0] = dir.tail[0];
cwd.tail[1] = dir.tail[1];
lfs_global_xor(&lfs->locals, &dir.locals);
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x3ff,
cwd.tail, sizeof(cwd.tail),
NULL));
if (err) {
return err;
}
}
return 0;
}
int lfs_rename(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;
int32_t oldtag = lfs_dir_lookup(lfs, &oldcwd, &oldpath);
if (oldtag < 0) {
return oldtag;
}
// find new entry
lfs_mdir_t newcwd;
int32_t prevtag = lfs_dir_lookup(lfs, &newcwd, &newpath);
if (prevtag < 0 && prevtag != LFS_ERR_NOENT) {
return prevtag;
}
uint16_t newid = lfs_tag_id(prevtag);
lfs_mdir_t prevdir;
if (prevtag != LFS_ERR_NOENT) {
// check that we have same type
if (lfs_tag_type(prevtag) != lfs_tag_type(oldtag)) {
return LFS_ERR_ISDIR;
}
if (lfs_tag_type(prevtag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t prevpair[2];
int32_t res = lfs_dir_get(lfs, &newcwd, 0x7c3ff000,
LFS_MKTAG(LFS_TYPE_STRUCT, newid, 8), prevpair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(prevpair);
// must be empty before removal
err = lfs_dir_fetch(lfs, &prevdir, prevpair);
if (err) {
return err;
}
if (prevdir.count > 0 || prevdir.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
lfs_global_deorphaned(lfs, false);
}
} else {
// check that name fits
lfs_size_t nlen = strlen(newpath);
if (nlen > lfs->name_max) {
return LFS_ERR_NAMETOOLONG;
}
// get next id
newid = newcwd.count;
}
// create move to fix later
lfs_global_move(lfs, oldcwd.pair, lfs_tag_id(oldtag));
// move over all attributes
err = lfs_dir_commit(lfs, &newcwd,
LFS_MKATTR(lfs_tag_type(oldtag), newid, newpath, strlen(newpath),
LFS_MKATTR(LFS_FROM_MOVE, newid, &oldcwd, lfs_tag_id(oldtag),
NULL)));
if (err) {
return err;
}
// let commit clean up after move (if we're different! otherwise move
// logic already fixed it for us)
if (lfs_pair_cmp(oldcwd.pair, newcwd.pair) != 0) {
err = lfs_dir_commit(lfs, &oldcwd, NULL);
if (err) {
return err;
}
}
if (prevtag != LFS_ERR_NOENT && lfs_tag_type(prevtag) == LFS_TYPE_DIR) {
err = lfs_fs_pred(lfs, prevdir.pair, &newcwd);
if (err) {
return err;
}
// fix orphan
lfs_global_deorphaned(lfs, true);
// steal state
newcwd.tail[0] = prevdir.tail[0];
newcwd.tail[1] = prevdir.tail[1];
lfs_global_xor(&lfs->locals, &prevdir.locals);
err = lfs_dir_commit(lfs, &newcwd,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x3ff,
newcwd.tail, sizeof(newcwd.tail),
NULL));
if (err) {
return err;
}
}
return 0;
}
lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
uint8_t type, void *buffer, lfs_size_t size) {
lfs_mdir_t cwd;
int32_t res = lfs_dir_lookup(lfs, &cwd, &path);
if (res < 0) {
return res;
}
res = lfs_dir_get(lfs, &cwd, 0x7ffff000,
LFS_MKTAG(0x100 | type, lfs_tag_id(res),
lfs_min(size, lfs->attr_max)), buffer);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
return (res == LFS_ERR_NOENT) ? 0 : lfs_tag_size(res);
}
int lfs_setattr(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;
}
lfs_mdir_t cwd;
int32_t res = lfs_dir_lookup(lfs, &cwd, &path);
if (res < 0) {
return res;
}
return lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(0x100 | type, lfs_tag_id(res), buffer, size,
NULL));
}
/// Filesystem operations ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
lfs->cfg = cfg;
int err = 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);
// 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 32-bits
LFS_ASSERT(lfs->cfg->lookahead % 32 == 0);
LFS_ASSERT(lfs->cfg->lookahead > 0);
if (lfs->cfg->lookahead_buffer) {
lfs->free.buffer = lfs->cfg->lookahead_buffer;
} else {
lfs->free.buffer = lfs_malloc(lfs->cfg->lookahead/8);
if (!lfs->free.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// check that the size limits are sane
LFS_ASSERT(lfs->cfg->inline_max <= LFS_INLINE_MAX);
LFS_ASSERT(lfs->cfg->inline_max <= lfs->cfg->cache_size);
lfs->inline_max = lfs->cfg->inline_max;
if (!lfs->inline_max) {
lfs->inline_max = lfs_min(LFS_INLINE_MAX, lfs->cfg->cache_size);
}
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->name_max <= LFS_NAME_MAX);
lfs->name_max = lfs->cfg->name_max;
if (!lfs->name_max) {
lfs->name_max = LFS_NAME_MAX;
}
// setup default state
lfs->root[0] = 0xffffffff;
lfs->root[1] = 0xffffffff;
lfs->mlist = NULL;
lfs->globals.s.movepair[0] = 0xffffffff;
lfs->globals.s.movepair[1] = 0xffffffff;
lfs->globals.s.moveid = 0x3ff;
lfs->globals.s.deorphaned = true;
lfs_global_zero(&lfs->locals);
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;
}
int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
lfs->free.off = 0;
lfs->free.size = lfs_min(lfs->cfg->lookahead, 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 = {
.magic = {"littlefs"},
.version = LFS_DISK_VERSION,
.block_size = lfs->cfg->block_size,
.block_count = lfs->cfg->block_count,
.attr_max = lfs->attr_max,
.name_max = lfs->name_max,
.inline_max = lfs->inline_max,
};
lfs_superblock_tole32(&superblock);
err = lfs_dir_commit(lfs, &root,
LFS_MKATTR(LFS_TYPE_SUPERBLOCK, 0, &superblock, sizeof(superblock),
LFS_MKATTR(LFS_TYPE_ROOT, 1, NULL, 0,
NULL)));
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;
}
int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// setup free lookahead
lfs->free.off = 0;
lfs->free.size = 0;
lfs->free.i = 0;
lfs_alloc_ack(lfs);
// load superblock
lfs_mdir_t root;
err = lfs_dir_fetch(lfs, &root, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
lfs_superblock_t superblock;
int32_t res = lfs_dir_get(lfs, &root, 0x7fc00000,
LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, sizeof(superblock)),
&superblock);
if (res < 0) {
err = res;
goto cleanup;
}
lfs_superblock_fromle32(&superblock);
// find root
int32_t tag = lfs_dir_find(lfs,
&root, (const lfs_block_t[2]){0, 1}, false, 0x7fc00000,
LFS_MKTAG(LFS_TYPE_ROOT, 0, 0), NULL);
if (tag < 0) {
return tag;
}
lfs->root[0] = root.pair[0];
lfs->root[1] = root.pair[1];
// 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 %"PRIu32".%"PRIu32,
major_version, minor_version);
err = LFS_ERR_INVAL;
goto cleanup;
}
// check superblock configuration
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.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.inline_max) {
if (superblock.inline_max > lfs->inline_max) {
LFS_ERROR("Unsupported inline_max (%"PRIu32" > %"PRIu32")",
superblock.inline_max, lfs->inline_max);
err = LFS_ERR_INVAL;
goto cleanup;
}
lfs->inline_max = superblock.inline_max;
}
// scan for any global updates
lfs_mdir_t dir = {.tail = {0, 1}};
while (!lfs_pair_isnull(dir.tail)) {
err = lfs_dir_fetch(lfs, &dir, dir.tail);
if (err) {
err = LFS_ERR_INVAL;
goto cleanup;
}
// xor together indirect deletes
lfs_global_xor(&lfs->locals, &dir.locals);
}
// update littlefs with globals
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->globals, &lfs->locals);
lfs_global_zero(&lfs->locals);
if (!lfs_pair_isnull(lfs->globals.s.movepair)) {
LFS_DEBUG("Found move %"PRIu32" %"PRIu32" %"PRIu32,
lfs->globals.s.movepair[0],
lfs->globals.s.movepair[1],
lfs->globals.s.moveid);
}
return 0;
cleanup:
lfs_unmount(lfs);
return err;
}
int lfs_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// Filesystem filesystem operations ///
int lfs_fs_traverse(lfs_t *lfs,
int (*cb)(void *data, lfs_block_t block), void *data) {
if (lfs_pair_isnull(lfs->root)) {
return 0;
}
// iterate over metadata pairs
lfs_mdir_t dir = {.tail = {0, 1}};
while (!lfs_pair_isnull(dir.tail)) {
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;
int32_t tag = lfs_dir_get(lfs, &dir, 0x7c3ff000,
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_type(tag) == LFS_TYPE_CTZSTRUCT) {
err = lfs_ctz_traverse(lfs, NULL, &lfs->rcache,
ctz.head, ctz.size, cb, data);
if (err) {
return err;
}
}
}
}
// 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;
}
}
}
return 0;
}
static int lfs_fs_pred(lfs_t *lfs,
const lfs_block_t pair[2], lfs_mdir_t *pdir) {
if (lfs_pair_isnull(lfs->root)) {
return LFS_ERR_NOENT;
}
// iterate over all directory directory entries
pdir->tail[0] = 0;
pdir->tail[1] = 1;
while (!lfs_pair_isnull(pdir->tail)) {
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;
}
static int32_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t pair[2],
lfs_mdir_t *parent) {
if (lfs_pair_isnull(lfs->root)) {
return LFS_ERR_NOENT;
}
// search for both orderings so we can reuse the find function
lfs_block_t child[2] = {pair[0], pair[1]};
lfs_pair_tole32(child);
for (int i = 0; i < 2; i++) {
int32_t tag = lfs_dir_find(lfs, parent,
(const lfs_block_t[2]){0, 1}, true, 0x7fc00fff,
LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, sizeof(child)), child);
if (tag != LFS_ERR_NOENT) {
return tag;
}
lfs_pair_swap(child);
}
return LFS_ERR_NOENT;
}
static int lfs_fs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], lfs_block_t newpair[2]) {
// update internal root
if (lfs_pair_cmp(oldpair, lfs->root) == 0) {
LFS_DEBUG("Relocating root %"PRIu32" %"PRIu32,
newpair[0], newpair[1]);
lfs->root[0] = newpair[0];
lfs->root[1] = newpair[1];
}
// update internally tracked dirs
for (lfs_mlist_t *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(oldpair, d->m.pair) == 0) {
d->m.pair[0] = newpair[0];
d->m.pair[1] = newpair[1];
}
}
// find parent
lfs_mdir_t parent;
int32_t tag = lfs_fs_parent(lfs, oldpair, &parent);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
if (tag != LFS_ERR_NOENT) {
// update disk, this creates a desync
lfs_global_deorphaned(lfs, false);
lfs_pair_tole32(newpair);
int err = lfs_dir_commit(lfs, &parent,
&(lfs_mattr_t){.tag=tag, .buffer=newpair});
lfs_pair_fromle32(newpair);
if (err) {
return err;
}
// clean up bad block, which should now be a desync
return lfs_fs_forceconsistency(lfs);
}
// find pred
int err = lfs_fs_pred(lfs, oldpair, &parent);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// if we can't find dir, it must be new
if (err != LFS_ERR_NOENT) {
// just replace bad pair, no desync can occur
parent.tail[0] = newpair[0];
parent.tail[1] = newpair[1];
err = lfs_dir_commit(lfs, &parent,
LFS_MKATTR(LFS_TYPE_TAIL + parent.split, 0x3ff,
parent.tail, sizeof(parent.tail),
NULL));
if (err) {
return err;
}
}
return 0;
}
static int lfs_fs_forceconsistency(lfs_t *lfs) {
if (!lfs->globals.s.deorphaned) {
LFS_DEBUG("Found orphans %"PRIu32,
lfs->globals.s.deorphaned);
// Fix any orphans
lfs_mdir_t pdir = {.split = true};
lfs_mdir_t dir = {.tail = {0, 1}};
// iterate over all directory directory entries
while (!lfs_pair_isnull(dir.tail)) {
int err = lfs_dir_fetch(lfs, &dir, dir.tail);
if (err) {
return err;
}
// check head blocks for orphans
if (!pdir.split) {
// check if we have a parent
lfs_mdir_t parent;
int32_t tag = lfs_fs_parent(lfs, pdir.tail, &parent);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
if (tag == LFS_ERR_NOENT) {
// we are an orphan
LFS_DEBUG("Fixing orphan %"PRIu32" %"PRIu32,
pdir.tail[0], pdir.tail[1]);
pdir.tail[0] = dir.tail[0];
pdir.tail[1] = dir.tail[1];
err = lfs_dir_commit(lfs, &pdir,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x3ff,
pdir.tail, sizeof(pdir.tail),
NULL));
if (err) {
return err;
}
break;
}
lfs_block_t pair[2];
int32_t res = lfs_dir_get(lfs, &parent, 0x7ffff000, tag, pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
if (!lfs_pair_sync(pair, pdir.tail)) {
// we have desynced
LFS_DEBUG("Fixing half-orphan %"PRIu32" %"PRIu32,
pair[0], pair[1]);
pdir.tail[0] = pair[0];
pdir.tail[1] = pair[1];
err = lfs_dir_commit(lfs, &pdir,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x3ff,
pdir.tail, sizeof(pdir.tail),
NULL));
if (err) {
return err;
}
break;
}
}
memcpy(&pdir, &dir, sizeof(pdir));
}
// mark orphan as fixed
lfs_global_deorphaned(lfs, false);
}
if (lfs->globals.s.moveid != 0x3ff) {
// Fix bad moves
LFS_DEBUG("Fixing move %"PRIu32" %"PRIu32" %"PRIu32,
lfs->globals.s.movepair[0],
lfs->globals.s.movepair[1],
lfs->globals.s.moveid);
// fetch and delete the moved entry
lfs_mdir_t movedir;
int err = lfs_dir_fetch(lfs, &movedir, lfs->globals.s.movepair);
if (err) {
return err;
}
// rely on cancel logic inside commit
err = lfs_dir_commit(lfs, &movedir, NULL);
if (err) {
return err;
}
}
return 0;
}
lfs_ssize_t lfs_fs_getattr(lfs_t *lfs,
uint8_t type, void *buffer, lfs_size_t size) {
lfs_mdir_t superdir;
int err = lfs_dir_fetch(lfs, &superdir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
int32_t res = lfs_dir_get(lfs, &superdir, 0x7ffff000,
LFS_MKTAG(0x100 | type, 0,
lfs_min(size, lfs->attr_max)), buffer);
if (res < 0) {
return res;
}
return (res == LFS_ERR_NOENT) ? 0 : lfs_tag_size(res);
}
int lfs_fs_setattr(lfs_t *lfs,
uint8_t type, const void *buffer, lfs_size_t size) {
if (size > lfs->attr_max) {
return LFS_ERR_NOSPC;
}
lfs_mdir_t superdir;
int err = lfs_dir_fetch(lfs, &superdir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
return lfs_dir_commit(lfs, &superdir,
LFS_MKATTR(0x100 | type, 0, buffer, size,
NULL));
}
static int lfs_fs_size_count(void *p, lfs_block_t block) {
(void)block;
lfs_size_t *size = p;
*size += 1;
return 0;
}
lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
lfs_size_t size = 0;
int err = lfs_fs_traverse(lfs, lfs_fs_size_count, &size);
if (err) {
return err;
}
return size;
}
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