嵌入式移植littlefs文件系统_littlefs文件系统异常文件异常err_corrupt
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
const lfs_off_t end = lfs_alignup(commit->off + 2sizeof(uint32_t),
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 off = commit->off + sizeof(lfs_tag_t);
lfs_off_t noff = lfs_min(end - off, 0x3fe) + off;
if (noff < end) {
noff = lfs_min(noff, end - 2*sizeof(uint32_t));
}
// read erased state from next program unit
lfs_tag_t tag = 0xffffffff;
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(tag),
commit->block, noff, &tag, sizeof(tag));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// build crc tag
bool reset = ~lfs_frombe32(tag) >> 31;
tag = LFS_MKTAG(LFS_TYPE_CRC + reset, 0x3ff, noff - off);
// write out crc
uint32_t footer[2];
footer[0] = lfs_tobe32(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,
&lfs->pcache, &lfs->rcache, false,
commit->block, commit->off, &footer, sizeof(footer));
if (err) {
return err;
}
// keep track of non-padding checksum to verify
if (off1 == 0) {
off1 = commit->off + sizeof(uint32_t);
crc1 = commit->crc;
}
commit->off += sizeof(tag)+lfs_tag_size(tag);
commit->ptag = tag ^ ((lfs_tag_t)reset << 31);
commit->crc = 0xffffffff; // reset crc for next "commit"
}
// flush buffers
int err = lfs_bd_sync(lfs, &lfs->pcache, &lfs->rcache, false);
if (err) {
return err;
}
// successful commit, check checksums to make sure
lfs_off_t off = commit->begin;
lfs_off_t noff = off1;
while (off < end) {
uint32_t crc = 0xffffffff;
for (lfs_off_t i = off; i < noff+sizeof(uint32_t); i++) {
// check against written crc, may catch blocks that
// become readonly and match our commit size exactly
if (i == off1 && crc != crc1) {
return LFS_ERR_CORRUPT;
}
// leave it up to caching to make this efficient
uint8_t dat;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, noff+sizeof(uint32_t)-i,
commit->block, i, &dat, 1);
if (err) {
return err;
}
crc = lfs_crc(crc, &dat, 1);
}
// detected write error?
if (crc != 0) {
return LFS_ERR_CORRUPT;
}
// skip padding
off = lfs_min(end - noff, 0x3fe) + noff;
if (off < end) {
off = lfs_min(off, end - 2*sizeof(uint32_t));
}
noff = off + sizeof(uint32_t);
}
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, crc, gstate,
// cleanup delete, and we cap at half a block to give room
// for metadata updates.
if (end - split < 0xff
&& size <= lfs_min(lfs->cfg->block_size - 36,
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 - 24;
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 cycle = 0;
while (!lfs_pair_isnull(dir.tail)) {
if (cycle >= lfs->cfg->block_count/2) {
// loop detected
err = LFS_ERR_CORRUPT;
goto cleanup;
}
cycle += 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 cycle = 0;
while (!lfs_pair_isnull(dir.tail)) {
if (cycle >= lfs->cfg->block_count/2) {
// loop detected
return LFS_ERR_CORRUPT;
}
cycle += 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 cycle = 0;
while (!lfs_pair_isnull(pdir->tail)) {
if (cycle >= lfs->cfg->block_count/2) {
// loop detected
return LFS_ERR_CORRUPT;
}
cycle += 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 cycle = 0;
while (!lfs_pair_isnull(parent->tail)) {
if (cycle >= lfs->cfg->block_count/2) {
// loop detected
return LFS_ERR_CORRUPT;
}
cycle += 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) > 0 || 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));
// 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;
restart:
{
// Fix any orphans
lfs_mdir_t pdir = {.split = true, .tail = {0, 1}};
lfs_mdir_t dir;
// 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;
}
// 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 (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) {
goto restart;
}
// refetch tail
continue;
}
if (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_sync(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) {
goto restart;
}
// refetch tail
continue;
}
}
}
pdir = dir;
}
}
// 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
#### lfs.h
/*
- The little filesystem
- Copyright © 2022, The littlefs authors.
- Copyright © 2017, Arm Limited. All rights reserved.
- SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS_H
#define LFS_H
#include <stdint.h>
#include <stdbool.h>
#include “lfs_util.h”
#ifdef __cplusplus
extern “C”
{
#endif
/// Version info ///
// Software library version
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS_VERSION 0x00020005
#define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
#define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >> 0))
// Version of On-disk data structures
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS_DISK_VERSION 0x00020000
#define LFS_DISK_VERSION_MAJOR (0xffff & (LFS_DISK_VERSION >> 16))
#define LFS_DISK_VERSION_MINOR (0xffff & (LFS_DISK_VERSION >> 0))
/// Definitions ///
// Type definitions
typedef uint32_t lfs_size_t;
typedef uint32_t lfs_off_t;
typedef int32_t lfs_ssize_t;
typedef int32_t lfs_soff_t;
typedef uint32_t lfs_block_t;
// Maximum name size in bytes, may be redefined to reduce the size of the
// info struct. Limited to <= 1022. Stored in superblock and must be
// respected by other littlefs drivers.
#ifndef LFS_NAME_MAX
#define LFS_NAME_MAX 255
#endif
// Maximum size of a file in bytes, may be redefined to limit to support other
// drivers. Limited on disk to <= 4294967296. However, above 2147483647 the
// functions lfs_file_seek, lfs_file_size, and lfs_file_tell will return
// incorrect values due to using signed integers. Stored in superblock and
// must be respected by other littlefs drivers.
#ifndef LFS_FILE_MAX
#define LFS_FILE_MAX 2147483647
#endif
// Maximum size of custom attributes in bytes, may be redefined, but there is
// no real benefit to using a smaller LFS_ATTR_MAX. Limited to <= 1022.
#ifndef LFS_ATTR_MAX
#define LFS_ATTR_MAX 1022
#endif
// Possible error codes, these are negative to allow
// valid positive return values
enum lfs_error {
LFS_ERR_OK = 0, // No error
LFS_ERR_IO = -5, // Error during device operation
LFS_ERR_CORRUPT = -84, // Corrupted
LFS_ERR_NOENT = -2, // No directory entry
LFS_ERR_EXIST = -17, // Entry already exists
LFS_ERR_NOTDIR = -20, // Entry is not a dir
LFS_ERR_ISDIR = -21, // Entry is a dir
LFS_ERR_NOTEMPTY = -39, // Dir is not empty
LFS_ERR_BADF = -9, // Bad file number
LFS_ERR_FBIG = -27, // File too large
LFS_ERR_INVAL = -22, // Invalid parameter
LFS_ERR_NOSPC = -28, // No space left on device
LFS_ERR_NOMEM = -12, // No more memory available
LFS_ERR_NOATTR = -61, // No data/attr available
LFS_ERR_NAMETOOLONG = -36, // File name too long
};
// File types
enum lfs_type {
// file types
LFS_TYPE_REG = 0x001,
LFS_TYPE_DIR = 0x002,
// internally used types
LFS_TYPE_SPLICE = 0x400,
LFS_TYPE_NAME = 0x000,
LFS_TYPE_STRUCT = 0x200,
LFS_TYPE_USERATTR = 0x300,
LFS_TYPE_FROM = 0x100,
LFS_TYPE_TAIL = 0x600,
LFS_TYPE_GLOBALS = 0x700,
LFS_TYPE_CRC = 0x500,
// internally used type specializations
LFS_TYPE_CREATE = 0x401,
LFS_TYPE_DELETE = 0x4ff,
LFS_TYPE_SUPERBLOCK = 0x0ff,
LFS_TYPE_DIRSTRUCT = 0x200,
LFS_TYPE_CTZSTRUCT = 0x202,
LFS_TYPE_INLINESTRUCT = 0x201,
LFS_TYPE_SOFTTAIL = 0x600,
LFS_TYPE_HARDTAIL = 0x601,
LFS_TYPE_MOVESTATE = 0x7ff,
// internal chip sources
LFS_FROM_NOOP = 0x000,
LFS_FROM_MOVE = 0x101,
LFS_FROM_USERATTRS = 0x102,
};
// File open flags
enum lfs_open_flags {
// open flags
LFS_O_RDONLY = 1, // Open a file as read only
#ifndef LFS_READONLY
LFS_O_WRONLY = 2, // Open a file as write only
LFS_O_RDWR = 3, // Open a file as read and write
LFS_O_CREAT = 0x0100, // Create a file if it does not exist
LFS_O_EXCL = 0x0200, // Fail if a file already exists
LFS_O_TRUNC = 0x0400, // Truncate the existing file to zero size
LFS_O_APPEND = 0x0800, // Move to end of file on every write
#endif
// internally used flags
#ifndef LFS_READONLY
LFS_F_DIRTY = 0x010000, // File does not match storage
LFS_F_WRITING = 0x020000, // File has been written since last flush
#endif
LFS_F_READING = 0x040000, // File has been read since last flush
#ifndef LFS_READONLY
LFS_F_ERRED = 0x080000, // An error occurred during write
#endif
LFS_F_INLINE = 0x100000, // Currently inlined in directory entry
};
// File seek flags
enum lfs_whence_flags {
LFS_SEEK_SET = 0, // Seek relative to an absolute position
LFS_SEEK_CUR = 1, // Seek relative to the current file position
LFS_SEEK_END = 2, // Seek relative to the end of the file
};
// Configuration provided during initialization of the littlefs
struct lfs_config {
// Opaque user provided context that can be used to pass
// information to the block device operations
void *context;
// Read a region in a block. Negative error codes are propagated
// to the user.
int (*read)(const struct lfs_config *c, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size);
// Program a region in a block. The block must have previously
// been erased. Negative error codes are propagated to the user.
// May return LFS_ERR_CORRUPT if the block should be considered bad.
int (*prog)(const struct lfs_config *c, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size);
// Erase a block. A block must be erased before being programmed.
// The state of an erased block is undefined. Negative error codes
// are propagated to the user.
// May return LFS_ERR_CORRUPT if the block should be considered bad.
int (*erase)(const struct lfs_config *c, lfs_block_t block);
// Sync the state of the underlying block device. Negative error codes
// are propagated to the user.
int (*sync)(const struct lfs_config *c);
#ifdef LFS_THREADSAFE
// Lock the underlying block device. Negative error codes
// are propagated to the user.
int (*lock)(const struct lfs_config *c);
// Unlock the underlying block device. Negative error codes
// are propagated to the user.
int (*unlock)(const struct lfs_config *c);
#endif
// Minimum size of a block read in bytes. All read operations will be a
// multiple of this value.
lfs_size_t read_size;
// Minimum size of a block program in bytes. All program operations will be
// a multiple of this value.
lfs_size_t prog_size;
// Size of an erasable block in bytes. This does not impact ram consumption
// and may be larger than the physical erase size. However, non-inlined
// files take up at minimum one block. Must be a multiple of the read and
// program sizes.
lfs_size_t block_size;
// Number of erasable blocks on the device.
lfs_size_t block_count;
// Number of erase cycles before littlefs evicts metadata logs and moves
// the metadata to another block. Suggested values are in the
// range 100-1000, with large values having better performance at the cost
// of less consistent wear distribution.
//
// Set to -1 to disable block-level wear-leveling.
int32_t block_cycles;
// Size of block caches in bytes. Each cache buffers a portion of a block in
// RAM. The littlefs needs a read cache, a program cache, and one additional
// cache per file. Larger caches can improve performance by storing more
// data and reducing the number of disk accesses. Must be a multiple of the
// read and program sizes, and a factor of the block size.
lfs_size_t cache_size;
// Size of the lookahead buffer in bytes. A larger lookahead buffer
// increases the number of blocks found during an allocation pass. The
// lookahead buffer is stored as a compact bitmap, so each byte of RAM
// can track 8 blocks. Must be a multiple of 8.
lfs_size_t lookahead_size;
// Optional statically allocated read buffer. Must be cache_size.
// By default lfs_malloc is used to allocate this buffer.
void *read_buffer;
// Optional statically allocated program buffer. Must be cache_size.
// By default lfs_malloc is used to allocate this buffer.
void *prog_buffer;
// Optional statically allocated lookahead buffer. Must be lookahead_size
// and aligned to a 32-bit boundary. By default lfs_malloc is used to
// allocate this buffer.
void *lookahead_buffer;
// Optional upper limit on length of file names in bytes. No downside for
// larger names except the size of the info struct which is controlled by
// the LFS_NAME_MAX define. Defaults to LFS_NAME_MAX when zero. Stored in
// superblock and must be respected by other littlefs drivers.
lfs_size_t name_max;
// Optional upper limit on files in bytes. No downside for larger files
// but must be <= LFS_FILE_MAX. Defaults to LFS_FILE_MAX when zero. Stored
// in superblock and must be respected by other littlefs drivers.
lfs_size_t file_max;
// Optional upper limit on custom attributes in bytes. No downside for
// larger attributes size but must be <= LFS_ATTR_MAX. Defaults to
// LFS_ATTR_MAX when zero.
lfs_size_t attr_max;
// Optional upper limit on total space given to metadata pairs in bytes. On
// devices with large blocks (e.g. 128kB) setting this to a low size (2-8kB)
// can help bound the metadata compaction time. Must be <= block_size.
// Defaults to block_size when zero.
lfs_size_t metadata_max;
};
// File info structure
struct lfs_info {
// Type of the file, either LFS_TYPE_REG or LFS_TYPE_DIR
uint8_t type;
// Size of the file, only valid for REG files. Limited to 32-bits.
lfs_size_t size;
// Name of the file stored as a null-terminated string. Limited to
// LFS_NAME_MAX+1, which can be changed by redefining LFS_NAME_MAX to
// reduce RAM. LFS_NAME_MAX is stored in superblock and must be
// respected by other littlefs drivers.
char name[LFS_NAME_MAX+1];
};
// Custom attribute structure, used to describe custom attributes
// committed atomically during file writes.
struct lfs_attr {
// 8-bit type of attribute, provided by user and used to
// identify the attribute
uint8_t type;
// Pointer to buffer containing the attribute
void *buffer;
// Size of attribute in bytes, limited to LFS_ATTR_MAX
lfs_size_t size;
};
// Optional configuration provided during lfs_file_opencfg
struct lfs_file_config {
// Optional statically allocated file buffer. Must be cache_size.
// By default lfs_malloc is used to allocate this buffer.
void *buffer;
// Optional list of custom attributes related to the file. If the file
// is opened with read access, these attributes will be read from disk
// during the open call. If the file is opened with write access, the
// attributes will be written to disk every file sync or close. This
// write occurs atomically with update to the file's contents.
//
// Custom attributes are uniquely identified by an 8-bit type and limited
// to LFS_ATTR_MAX bytes. When read, if the stored attribute is smaller
// than the buffer, it will be padded with zeros. If the stored attribute
// is larger, then it will be silently truncated. If the attribute is not
// found, it will be created implicitly.
struct lfs_attr *attrs;
// Number of custom attributes in the list
lfs_size_t attr_count;
};
/// internal littlefs data structures ///
typedef struct lfs_cache {
lfs_block_t block;
lfs_off_t off;
lfs_size_t size;
uint8_t *buffer;
} lfs_cache_t;
typedef struct lfs_mdir {
lfs_block_t pair[2];
uint32_t rev;
lfs_off_t off;
uint32_t etag;
uint16_t count;
bool erased;
bool split;
lfs_block_t tail[2];
} lfs_mdir_t;
// littlefs directory type
typedef struct lfs_dir {
struct lfs_dir *next;
uint16_t id;
uint8_t type;
lfs_mdir_t m;
lfs_off_t pos;
lfs_block_t head[2];
} lfs_dir_t;
// littlefs file type
typedef struct lfs_file {
struct lfs_file *next;
uint16_t id;
uint8_t type;
lfs_mdir_t m;
struct lfs_ctz {
lfs_block_t head;
lfs_size_t size;
} ctz;
uint32_t flags;
lfs_off_t pos;
lfs_block_t block;
lfs_off_t off;
lfs_cache_t cache;
const struct lfs_file_config *cfg;
} lfs_file_t;
typedef struct lfs_superblock {
uint32_t version;
lfs_size_t block_size;
lfs_size_t block_count;
lfs_size_t name_max;
lfs_size_t file_max;
lfs_size_t attr_max;
} lfs_superblock_t;
typedef struct lfs_gstate {
uint32_t tag;
lfs_block_t pair[2];
} lfs_gstate_t;
// The littlefs filesystem type
typedef struct lfs {
lfs_cache_t rcache;
lfs_cache_t pcache;
lfs_block_t root[2];
struct lfs_mlist {
struct lfs_mlist *next;
uint16_t id;
uint8_t type;
lfs_mdir_t m;
} *mlist;
uint32_t seed;
lfs_gstate_t gstate;
lfs_gstate_t gdisk;
lfs_gstate_t gdelta;
struct lfs_free {
lfs_block_t off;
lfs_block_t size;
lfs_block_t i;
lfs_block_t ack;
uint32_t *buffer;
} free;
const struct lfs_config *cfg;
lfs_size_t name_max;
lfs_size_t file_max;
lfs_size_t attr_max;
#ifdef LFS_MIGRATE
struct lfs1 *lfs1;
#endif
} lfs_t;
/// Filesystem functions ///
#ifndef LFS_READONLY
// Format a block device with the littlefs
//
// Requires a littlefs object and config struct. This clobbers the littlefs
// object, and does not leave the filesystem mounted. The config struct must
// be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs_format(lfs_t *lfs, const struct lfs_config *config);
#endif
// Mounts a littlefs
//
// Requires a littlefs object and config struct. Multiple filesystems
// may be mounted simultaneously with multiple littlefs objects. Both
// lfs and config must be allocated while mounted. The config struct must
// be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs_mount(lfs_t *lfs, const struct lfs_config *config);
// Unmounts a littlefs
//
// Does nothing besides releasing any allocated resources.
// Returns a negative error code on failure.
int lfs_unmount(lfs_t *lfs);
/// General operations ///
#ifndef LFS_READONLY
// Removes a file or directory
//
// If removing a directory, the directory must be empty.
// Returns a negative error code on failure.
int lfs_remove(lfs_t *lfs, const char *path);
#endif
#ifndef LFS_READONLY
// Rename or move a file or directory
//
// If the destination exists, it must match the source in type.
// If the destination is a directory, the directory must be empty.
//
// Returns a negative error code on failure.
int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath);
#endif
// Find info about a file or directory
//
// Fills out the info structure, based on the specified file or directory.
// Returns a negative error code on failure.
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
// Get a custom attribute
//
// Custom attributes are uniquely identified by an 8-bit type and limited
// to LFS_ATTR_MAX bytes. When read, if the stored attribute is smaller than
// the buffer, it will be padded with zeros. If the stored attribute is larger,
// then it will be silently truncated. If no attribute is found, the error
// LFS_ERR_NOATTR is returned and the buffer is filled with zeros.
//
// Returns the size of the attribute, or a negative error code on failure.
// Note, the returned size is the size of the attribute on disk, irrespective
// of the size of the buffer. This can be used to dynamically allocate a buffer
// or check for existence.
lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
uint8_t type, void *buffer, lfs_size_t size);
#ifndef LFS_READONLY
// Set custom attributes
//
// Custom attributes are uniquely identified by an 8-bit type and limited
// to LFS_ATTR_MAX bytes. If an attribute is not found, it will be
// implicitly created.
//
// Returns a negative error code on failure.
int lfs_setattr(lfs_t *lfs, const char *path,
uint8_t type, const void *buffer, lfs_size_t size);
#endif
#ifndef LFS_READONLY
// Removes a custom attribute
//
// If an attribute is not found, nothing happens.
//
// Returns a negative error code on failure.
int lfs_removeattr(lfs_t *lfs, const char *path, uint8_t type);
#endif
/// File operations ///
#ifndef LFS_NO_MALLOC
// Open a file
//
// The mode that the file is opened in is determined by the flags, which
// are values from the enum lfs_open_flags that are bitwise-ored together.
//
// Returns a negative error code on failure.
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags);
// if LFS_NO_MALLOC is defined, lfs_file_open() will fail with LFS_ERR_NOMEM
// thus use lfs_file_opencfg() with config.buffer set.
#endif
// Open a file with extra configuration
//
// The mode that the file is opened in is determined by the flags, which
// are values from the enum lfs_open_flags that are bitwise-ored together.
//
// The config struct provides additional config options per file as described
// above. The config struct must remain allocated while the file is open, and
// the config struct must be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags,
const struct lfs_file_config *config);
// Close a file
//
// Any pending writes are written out to storage as though
// sync had been called and releases any allocated resources.
//
// Returns a negative error code on failure.
int lfs_file_close(lfs_t *lfs, lfs_file_t *file);
// Synchronize a file on storage
//
// Any pending writes are written out to storage.
// Returns a negative error code on failure.
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file);
// Read data from file
//
// Takes a buffer and size indicating where to store the read data.
// Returns the number of bytes read, or a negative error code on failure.
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size);
#ifndef LFS_READONLY
// Write data to file
//
// Takes a buffer and size indicating the data to write. The file will not
// actually be updated on the storage until either sync or close is called.
//
// Returns the number of bytes written, or a negative error code on failure.
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size);
#endif
// Change the position of the file
//
// The change in position is determined by the offset and whence flag.
// Returns the new position of the file, or a negative error code on failure.
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence);
#ifndef LFS_READONLY
// Truncates the size of the file to the specified size
//
// Returns a negative error code on failure.
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size);
#endif
// Return the position of the file
//
// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
// Returns the position of the file, or a negative error code on failure.
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file);
// Change the position of the file to the beginning of the file
//
// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_SET)
// Returns a negative error code on failure.
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file);
// Return the size of the file
//
// Similar to lfs_file_seek(lfs, file, 0, LFS_SEEK_END)
// Returns the size of the file, or a negative error code on failure.
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file);
/// Directory operations ///
#ifndef LFS_READONLY
// Create a directory
//
// Returns a negative error code on failure.
int lfs_mkdir(lfs_t *lfs, const char *path);
#endif
// Open a directory
//
// Once open a directory can be used with read to iterate over files.
// Returns a negative error code on failure.
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path);
// Close a directory
//
// Releases any allocated resources.
// Returns a negative error code on failure.
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir);
// Read an entry in the directory
//
// Fills out the info structure, based on the specified file or directory.
// Returns a positive value on success, 0 at the end of directory,
// or a negative error code on failure.
int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info);
// Change the position of the directory
//
// The new off must be a value previous returned from tell and specifies
// an absolute offset in the directory seek.
//
// Returns a negative error code on failure.
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off);
// Return the position of the directory
//
// The returned offset is only meant to be consumed by seek and may not make
// sense, but does indicate the current position in the directory iteration.
//
// Returns the position of the directory, or a negative error code on failure.
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir);
// Change the position of the directory to the beginning of the directory
//
// Returns a negative error code on failure.
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir);
/// Filesystem-level filesystem operations
// Finds the current size of the filesystem
//
// Note: Result is best effort. If files share COW structures, the returned
// size may be larger than the filesystem actually is.
//
// Returns the number of allocated blocks, or a negative error code on failure.
lfs_ssize_t lfs_fs_size(lfs_t *lfs);
// Traverse through all blocks in use by the filesystem
//
// The provided callback will be called with each block address that is
// currently in use by the filesystem. This can be used to determine which
// blocks are in use or how much of the storage is available.
//
// Returns a negative error code on failure.
int lfs_fs_traverse(lfs_t *lfs, int (cb)(void, lfs_block_t), void *data);
#ifndef LFS_READONLY
#ifdef LFS_MIGRATE
// Attempts to migrate a previous version of littlefs
//
// Behaves similarly to the lfs_format function. Attempts to mount
// the previous version of littlefs and update the filesystem so it can be
// mounted with the current version of littlefs.
//
// Requires a littlefs object and config struct. This clobbers the littlefs
// object, and does not leave the filesystem mounted. The config struct must
// be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg);
#endif
#endif
#ifdef __cplusplus
} /* extern “C” */
#endif
#endif
#### lfs\_util.c
/*
- lfs util functions
- Copyright © 2022, The littlefs authors.
- Copyright © 2017, Arm Limited. All rights reserved.
- SPDX-License-Identifier: BSD-3-Clause
*/
#include “lfs_util.h”
// Only compile if user does not provide custom config
#ifndef LFS_CONFIG
// Software CRC implementation with small lookup table
uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size) {
static const uint32_t rtable[16] = {
0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
};
const uint8_t *data = buffer;
for (size_t i = 0; i < size; i++) {
crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 0)) & 0xf];
crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 4)) & 0xf];
}
return crc;
}
#endif
#### lfs\_util.h
/*
- lfs utility functions
- Copyright © 2022, The littlefs authors.
- Copyright © 2017, Arm Limited. All rights reserved.
- SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS_UTIL_H
#define LFS_UTIL_H
// Users can override lfs_util.h with their own configuration by defining
// LFS_CONFIG as a header file to include (-DLFS_CONFIG=lfs_config.h).
//
// If LFS_CONFIG is used, none of the default utils will be emitted and must be
// provided by the config file. To start, I would suggest copying lfs_util.h
// and modifying as needed.
#ifdef LFS_CONFIG
#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
#define LFS_STRINGIZE2(x) #x
#include LFS_STRINGIZE(LFS_CONFIG)
#else
// System includes
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <inttypes.h>
#ifndef LFS_NO_MALLOC
#include <stdlib.h>
#endif
#ifndef LFS_NO_ASSERT
#include <assert.h>
#endif
#if !defined(LFS_NO_DEBUG) ||
!defined(LFS_NO_WARN) ||
!defined(LFS_NO_ERROR) ||
defined(LFS_YES_TRACE)
#include <stdio.h>
#endif
#ifdef __cplusplus
extern “C”
{
#endif
// Macros, may be replaced by system specific wrappers. Arguments to these
// macros must not have side-effects as the macros can be removed for a smaller
// code footprint
// Logging functions
#ifndef LFS_TRACE
#ifdef LFS_YES_TRACE
#define LFS_TRACE_(fmt, …)
printf("%s:%d:trace: " fmt “%s\n”, FILE, LINE, VA_ARGS)
#define LFS_TRACE(…) LFS_TRACE_(VA_ARGS, “”)
#else
#define LFS_TRACE(…)
#endif
#endif
#ifndef LFS_DEBUG
#ifndef LFS_NO_DEBUG
#define LFS_DEBUG_(fmt, …)
printf("%s:%d:debug: " fmt “%s\n”, FILE, LINE, VA_ARGS)
#define LFS_DEBUG(…) LFS_DEBUG_(VA_ARGS, “”)
#else
#define LFS_DEBUG(…)
#endif
#endif
#ifndef LFS_WARN
#ifndef LFS_NO_WARN
#define LFS_WARN_(fmt, …)
printf("%s:%d:warn: " fmt “%s\n”, FILE, LINE, VA_ARGS)
#define LFS_WARN(…) LFS_WARN_(VA_ARGS, “”)
#else
#define LFS_WARN(…)
#endif
#endif
#ifndef LFS_ERROR
#ifndef LFS_NO_ERROR
#define LFS_ERROR_(fmt, …)
printf("%s:%d:error: " fmt “%s\n”, FILE, LINE, VA_ARGS)
#define LFS_ERROR(…) LFS_ERROR_(VA_ARGS, “”)
#else
#define LFS_ERROR(…)
#endif
#endif
// Runtime assertions
#ifndef LFS_ASSERT
#ifndef LFS_NO_ASSERT
#define LFS_ASSERT(test) assert(test)
#else
#define LFS_ASSERT(test)
#endif
#endif
// Builtin functions, these may be replaced by more efficient
// toolchain-specific implementations. LFS_NO_INTRINSICS falls back to a more
// expensive basic C implementation for debugging purposes
// Min/max functions for unsigned 32-bit numbers
static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
return (a > b) ? a : b;
}
static inline uint32_t lfs_min(uint32_t a, uint32_t b) {
return (a < b) ? a : b;
}
// Align to nearest multiple of a size
static inline uint32_t lfs_aligndown(uint32_t a, uint32_t alignment) {
return a - (a % alignment);
}
static inline uint32_t lfs_alignup(uint32_t a, uint32_t alignment) {
return lfs_aligndown(a + alignment-1, alignment);
}
// Find the smallest power of 2 greater than or equal to a
static inline uint32_t lfs_npw2(uint32_t a) {
#if !defined(LFS_NO_INTRINSICS) && (defined(GNUC) || defined(__CC_ARM))
return 32 - __builtin_clz(a-1);
#else
uint32_t r = 0;
uint32_t s;
a -= 1;
s = (a > 0xffff) << 4; a >>= s; r |= s;
s = (a > 0xff ) << 3; a >>= s; r |= s;
s = (a > 0xf ) << 2; a >>= s; r |= s;
s = (a > 0x3 ) << 1; a >>= s; r |= s;
return (r | (a >> 1)) + 1;
#endif
}
// Count the number of trailing binary zeros in a
// lfs_ctz(0) may be undefined
static inline uint32_t lfs_ctz(uint32_t a) {
#if !defined(LFS_NO_INTRINSICS) && defined(GNUC)
return __builtin_ctz(a);
#else
return lfs_npw2((a & -a) + 1) - 1;
#endif
}
// Count the number of binary ones in a
static inline uint32_t lfs_popc(uint32_t a) {
#if !defined(LFS_NO_INTRINSICS) && (defined(GNUC) || defined(__CC_ARM))
return __builtin_popcount(a);
#else
a = a - ((a >> 1) & 0x55555555);
a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
#endif
}
// Find the sequence comparison of a and b, this is the distance
// between a and b ignoring overflow
static inline int lfs_scmp(uint32_t a, uint32_t b) {
return (int)(unsigned)(a - b);
}
// Convert between 32-bit little-endian and native order
static inline uint32_t lfs_fromle32(uint32_t a) {
#if (defined( BYTE_ORDER ) && defined( ORDER_LITTLE_ENDIAN ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) ||
(defined(__BYTE_ORDER ) && defined(__ORDER_LITTLE_ENDIAN ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) ||
(defined(BYTE_ORDER) && defined(ORDER_LITTLE_ENDIAN) && BYTE_ORDER == ORDER_LITTLE_ENDIAN)
return a;
#elif !defined(LFS_NO_INTRINSICS) && (
(defined( BYTE_ORDER ) && defined( ORDER_BIG_ENDIAN ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) ||
(defined(__BYTE_ORDER ) && defined(__ORDER_BIG_ENDIAN ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) ||
(defined(BYTE_ORDER) && defined(ORDER_BIG_ENDIAN) && BYTE_ORDER == ORDER_BIG_ENDIAN))
return __builtin_bswap32(a);
#else
return (((uint8_t*)&a)[0] << 0) |
(((uint8_t*)&a)[1] << 8) |
(((uint8_t*)&a)[2] << 16) |
(((uint8_t*)&a)[3] << 24);
#endif
}
static inline uint32_t lfs_tole32(uint32_t a) {
return lfs_fromle32(a);
}
// Convert between 32-bit big-endian and native order
static inline uint32_t lfs_frombe32(uint32_t a) {
#if !defined(LFS_NO_INTRINSICS) && (
(defined( BYTE_ORDER ) && defined( ORDER_LITTLE_ENDIAN ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) ||
(defined(__BYTE_ORDER ) && defined(__ORDER_LITTLE_ENDIAN ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) ||
(defined(BYTE_ORDER) && defined(ORDER_LITTLE_ENDIAN) && BYTE_ORDER == ORDER_LITTLE_ENDIAN))
return __builtin_bswap32(a);
#elif (defined( BYTE_ORDER ) && defined( ORDER_BIG_ENDIAN ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) ||
(defined(__BYTE_ORDER ) && defined(__ORDER_BIG_ENDIAN ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) ||
(defined(BYTE_ORDER) && defined(ORDER_BIG_ENDIAN) && BYTE_ORDER == ORDER_BIG_ENDIAN)
return a;
#else
return (((uint8_t*)&a)[0] << 24) |
(((uint8_t*)&a)[1] << 16) |
(((uint8_t*)&a)[2] << 8) |
(((uint8_t*)&a)[3] << 0);
#endif
}
static inline uint32_t lfs_tobe32(uint32_t a) {
return lfs_frombe32(a);
}
// Calculate CRC-32 with polynomial = 0x04c11db7
uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size);
// Allocate memory, only used if buffers are not provided to littlefs
// Note, memory must be 64-bit aligned
static inline void *lfs_malloc(size_t size) {
#ifndef LFS_NO_MALLOC
return malloc(size);
#else
(void)size;
return NULL;
#endif
}
// Deallocate memory, only used if buffers are not provided to littlefs
static inline void lfs_free(void *p) {
#ifndef LFS_NO_MALLOC
free§;
#else
(void)p;
#endif
}
#ifdef __cplusplus
} /* extern “C” */
#endif
#endif
#endif
#### lfs\_port.c
#define GLOBLE_FS_PORT
#include “W25Qxx.h”
#include “lfs.h”
#include “lfs_port.h”
lfs_t lfs; // lfs 文件系统对象
lfs_file_t file; // lfs 文件对象
struct lfs_config lfs_cfg; // lfs 文件系统配置结构体
/*
- @brief 从指定块内的某区域读数据
- @param [in] lfs_config格式参数
- @param [in] block 逻辑块索引号，从0开始
- @param [in] off 块内偏移，该值需能被read_size整除
- @param [out] 读出数据的输出缓冲区
- @param [in] size 要读取的字节数，该值需能被read_size整除，lfs在读取时会确保不会跨块；
- @retval 0 成功, < 0 错误码
*/
int lfs_spi_flash_read(const struct lfs_config *cfg, lfs_block_t block, lfs_off_t off, void *buffer, lfs_size_t size) {
// check if read is valid
LFS_ASSERT(off % cfg->read_size == 0);
LFS_ASSERT(size % cfg->read_size == 0);
LFS_ASSERT(block < cfg->block_count);
W25QXX_Read((uint8_t *)buffer,block * cfg->block_size + off, size);
return LFS_ERR_OK;
}
/*
- @brief 将数据写入指定块内的某区域。该区域必须已经先被擦除过，可以返回 LFS_ERR_CORRUPT 表示该块已损坏
- @param [in] lfs_config格式参数
- @param [in] block 逻辑块索引号，从0开始
- @param [in] off 块内偏移，该值需能被rprog_size整除
- @param [in] 写入数据的缓冲区
- @param [in] size 要写入的字节数，该值需能被read_size整除，lfs在读取时会确保不会跨块；
- @retval 0 成功, < 0 错误码
*/
int lfs_spi_flash_prog(const struct lfs_config *cfg, lfs_block_t block, lfs_off_t off, const void *buffer, lfs_size_t size) {
// check if write is valid
LFS_ASSERT(off % cfg->prog_size == 0);
LFS_ASSERT(size % cfg->prog_size == 0);
LFS_ASSERT(block < cfg->block_count);
W25QXX_Write((uint8_t *)buffer,block * cfg->block_size + off, size);
return LFS_ERR_OK;
}
/*
- @brief 擦除指定块。块在写入之前必须先被擦除过，被擦除块的状态是未定义
- @param [in] lfs_config格式参数
- @param [in] block 要擦除的逻辑块索引号，从0开始
- @retval 0 成功, < 0 错误码
*/
int lfs_spi_flash_erase(const struct lfs_config *cfg, lfs_block_t block) {
// check if erase is valid
LFS_ASSERT(block < cfg->block_count);
W25QXX_Erase_Sector(block * cfg->block_size);
return LFS_ERR_OK;
}
/*
- @brief 对底层块设备做同步操作。若底层块设备不没有同步这项操作可以直接返回
- @param [in] lfs_config格式参数;
- @retval 0 成功, < 0 错误码
*/
int lfs_spi_flash_sync(const struct lfs_config *cfg) {
return LFS_ERR_OK;
}
/*
-
@brief SPI_FLASH—littlefs初始化
-
@param [in]无;
-
@retval 0 成功, < 0 错误码
*/
int lfs_spi_flash_init(void)
{
if(W25QXX_Init())
{
lfs_cfg.read = lfs_spi_flash_read;
lfs_cfg.prog = lfs_spi_flash_prog;
lfs_cfg.erase = lfs_spi_flash_erase;
lfs_cfg.sync = lfs_spi_flash_sync;// 最小读取字节数，所有的读取操作字节数必须是它的整数倍 lfs_cfg.read_size = 16; // 最小写入字节数，所有的写入操作字节数必须是它的整数倍 lfs_cfg.prog_size = 16; // 擦除块操作的字节数，该选项不影响 RAM 消耗，可以比物理擦除尺寸大 // 但是每个文件至少占用一个块，必须是读取和写入操作字节数的整数倍 lfs_cfg.block_size = W25QXX_SECTOR_SIZE; // 设备上可擦除块的数量，即容量 lfs_cfg.block_count = W25QXX_SECTOR_NUMBER; // littlefs 系统删除元数据日志并将元数据移动到另一个块之前的擦除周期数。 // 建议取值范围为 100 ~ 1000，较大数值有较好的性能但是会导致磨损分布不一致 // 取值 -1 的话，即为禁用块级磨损均衡 lfs_cfg.block_cycles = 500; // 块缓存大小，每个缓存都会在 RAM 中缓冲一部分块数据， // littlefs 系统需要一个读取缓存、一个写入缓存，每个文件还需要一个额外的缓存。 // 更大的缓存可以通过存储更多的数据并降低磁盘访问数量等手段来提高性能 lfs_cfg.cache_size = 16; // 先行缓冲大小，更大的先行缓冲可以提高分配操作中可被发现的块数量 // 即分配块时每次步进多少个块，16就表示每次分配16个块 // 先行缓冲以紧凑的bit位形式来存储，故 RAM 中的一个字节可以对应8个块 // 该值必须是8的整数倍 lfs_cfg.lookahead_size = 16; return LFS_ERR_OK;} else
{
return LFS_ERR_IO;
}
}
//文件系统初始化
void lfs_init_test(void)
{
int temp = 0;
// mount the filesystem
int err = lfs_mount(&lfs, &lfs_cfg);
// reformat if we can not mount the filesystem
// this should only happen on the first boot
if (err) {
err = lfs_format(&lfs, &lfs_cfg);
err = lfs_mount(&lfs, &lfs_cfg);
}
lfs_file_open(&lfs, &file, “test”, LFS_O_RDWR | LFS_O_CREAT);
lfs_file_read(&lfs, &file, &temp, sizeof(temp));
temp = 1;
lfs_file_write(&lfs, &file, &temp , sizeof(temp ));
// remember the storage is not updated until the file is closed successfully
lfs_file_close(&lfs, &file);
// release any resources we were using
lfs_unmount(&lfs);
}
#### lfs\_port.h
#ifndef LFS_PORT_H
#define LFS_PORT_H
#ifdef GLOBLE_LFS_PORT
#define EXT_LFS
魔乐社区（Modelers.cn) 是一个中立、公益的人工智能社区，提供人工智能工具、模型、数据的托管、展示与应用协同服务，为人工智能开发及爱好者搭建开放的学习交流平台。社区通过理事会方式运作，由全产业链共同建设、共同运营、共同享有，推动国产AI生态繁荣发展。
更多推荐
13
0- 0
已为社区贡献5条内容
所有评论(0)