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thirdparty-littlefs/lfs.c
Christopher Haster 746b90965c Added lfs_fs_size for finding a count of used blocks 
This has existed for some time in the form of the lfs_traverse
function, through which a user could provide a simple callback that
would just count the number of blocks lfs_traverse finds. However,
this approach is relatively unconventional and has proven to be confusing
for most users.
2018-10-09 23:02:57 -05:00

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/*
* The little filesystem
*
* Copyright (c) 2017 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "lfs.h"
#include "lfs_util.h"
/// Caching block device operations ///
static int lfs_cache_read(lfs_t *lfs, lfs_cache_t *rcache,
const lfs_cache_t *pcache, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff);
while (size > 0) {
if (pcache && block == pcache->block && off >= pcache->off &&
off < pcache->off + lfs->cfg->prog_size) {
// is already in pcache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->prog_size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
if (block == rcache->block && off >= rcache->off &&
off < rcache->off + lfs->cfg->read_size) {
// is already in rcache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->read_size - (off-rcache->off));
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
if (off % lfs->cfg->read_size == 0 && size >= lfs->cfg->read_size) {
// bypass cache?
lfs_size_t diff = size - (size % lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
data += diff;
off += diff;
size -= diff;
continue;
}
// load to cache, first condition can no longer fail
LFS_ASSERT(block < lfs->cfg->block_count);
rcache->block = block;
rcache->off = off - (off % lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, rcache->block,
rcache->off, rcache->buffer, lfs->cfg->read_size);
if (err) {
return err;
}
}
return 0;
}
static int lfs_cache_cmp(lfs_t *lfs, lfs_cache_t *rcache,
const lfs_cache_t *pcache, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
for (lfs_off_t i = 0; i < size; i++) {
uint8_t c;
int err = lfs_cache_read(lfs, rcache, pcache,
block, off+i, &c, 1);
if (err) {
return err;
}
if (c != data[i]) {
return false;
}
}
return true;
}
static int lfs_cache_crc(lfs_t *lfs, lfs_cache_t *rcache,
const lfs_cache_t *pcache, lfs_block_t block,
lfs_off_t off, lfs_size_t size, uint32_t *crc) {
for (lfs_off_t i = 0; i < size; i++) {
uint8_t c;
int err = lfs_cache_read(lfs, rcache, pcache,
block, off+i, &c, 1);
if (err) {
return err;
}
lfs_crc(crc, &c, 1);
}
return 0;
}
static int lfs_cache_flush(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache) {
if (pcache->block != 0xffffffff) {
LFS_ASSERT(pcache->block < lfs->cfg->block_count);
int err = lfs->cfg->prog(lfs->cfg, pcache->block,
pcache->off, pcache->buffer, lfs->cfg->prog_size);
if (err) {
return err;
}
if (rcache) {
int res = lfs_cache_cmp(lfs, rcache, NULL, pcache->block,
pcache->off, pcache->buffer, lfs->cfg->prog_size);
if (res < 0) {
return res;
}
if (!res) {
return LFS_ERR_CORRUPT;
}
}
pcache->block = 0xffffffff;
}
return 0;
}
static int lfs_cache_prog(lfs_t *lfs, lfs_cache_t *pcache,
lfs_cache_t *rcache, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff);
LFS_ASSERT(off + size <= lfs->cfg->block_size);
while (size > 0) {
if (block == pcache->block && off >= pcache->off &&
off < pcache->off + lfs->cfg->prog_size) {
// is already in pcache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->prog_size - (off-pcache->off));
memcpy(&pcache->buffer[off-pcache->off], data, diff);
data += diff;
off += diff;
size -= diff;
if (off % lfs->cfg->prog_size == 0) {
// eagerly flush out pcache if we fill up
int err = lfs_cache_flush(lfs, pcache, rcache);
if (err) {
return err;
}
}
continue;
}
// pcache must have been flushed, either by programming and
// entire block or manually flushing the pcache
LFS_ASSERT(pcache->block == 0xffffffff);
if (off % lfs->cfg->prog_size == 0 &&
size >= lfs->cfg->prog_size) {
// bypass pcache?
LFS_ASSERT(block < lfs->cfg->block_count);
lfs_size_t diff = size - (size % lfs->cfg->prog_size);
int err = lfs->cfg->prog(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
if (rcache) {
int res = lfs_cache_cmp(lfs, rcache, NULL,
block, off, data, diff);
if (res < 0) {
return res;
}
if (!res) {
return LFS_ERR_CORRUPT;
}
}
data += diff;
off += diff;
size -= diff;
continue;
}
// prepare pcache, first condition can no longer fail
pcache->block = block;
pcache->off = off - (off % lfs->cfg->prog_size);
}
return 0;
}
/// General lfs block device operations ///
static int lfs_bd_read(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
// if we ever do more than writes to alternating pairs,
// this may need to consider pcache
return lfs_cache_read(lfs, &lfs->rcache, NULL,
block, off, buffer, size);
}
static int lfs_bd_prog(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
return lfs_cache_prog(lfs, &lfs->pcache, NULL,
block, off, buffer, size);
}
static int lfs_bd_cmp(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
return lfs_cache_cmp(lfs, &lfs->rcache, NULL, block, off, buffer, size);
}
static int lfs_bd_crc(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, lfs_size_t size, uint32_t *crc) {
return lfs_cache_crc(lfs, &lfs->rcache, NULL, block, off, size, crc);
}
static int lfs_bd_erase(lfs_t *lfs, lfs_block_t block) {
LFS_ASSERT(block < lfs->cfg->block_count);
return lfs->cfg->erase(lfs->cfg, block);
}
static int lfs_bd_sync(lfs_t *lfs) {
lfs->rcache.block = 0xffffffff;
int err = lfs_cache_flush(lfs, &lfs->pcache, NULL);
if (err) {
return err;
}
return lfs->cfg->sync(lfs->cfg);
}
/// Internal operations predeclared here ///
int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
static int lfs_pred(lfs_t *lfs, const lfs_block_t dir[2], lfs_dir_t *pdir);
static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_dir_t *parent, lfs_entry_t *entry);
static int lfs_moved(lfs_t *lfs, const void *e);
static int lfs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], const lfs_block_t newpair[2]);
int lfs_deorphan(lfs_t *lfs);
/// Block allocator ///
static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
lfs_t *lfs = p;
lfs_block_t off = ((block - lfs->free.off)
+ lfs->cfg->block_count) % lfs->cfg->block_count;
if (off < lfs->free.size) {
lfs->free.buffer[off / 32] |= 1U << (off % 32);
}
return 0;
}
static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
while (true) {
while (lfs->free.i != lfs->free.size) {
lfs_block_t off = lfs->free.i;
lfs->free.i += 1;
lfs->free.ack -= 1;
if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
// found a free block
*block = (lfs->free.off + off) % lfs->cfg->block_count;
// eagerly find next off so an alloc ack can
// discredit old lookahead blocks
while (lfs->free.i != lfs->free.size &&
(lfs->free.buffer[lfs->free.i / 32]
& (1U << (lfs->free.i % 32)))) {
lfs->free.i += 1;
lfs->free.ack -= 1;
}
return 0;
}
}
// check if we have looked at all blocks since last ack
if (lfs->free.ack == 0) {
LFS_WARN("No more free space %d", lfs->free.i + lfs->free.off);
return LFS_ERR_NOSPC;
}
lfs->free.off = (lfs->free.off + lfs->free.size)
% lfs->cfg->block_count;
lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->free.ack);
lfs->free.i = 0;
// find mask of free blocks from tree
memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
int err = lfs_traverse(lfs, lfs_alloc_lookahead, lfs);
if (err) {
return err;
}
}
}
static void lfs_alloc_ack(lfs_t *lfs) {
lfs->free.ack = lfs->cfg->block_count;
}
/// Endian swapping functions ///
static void lfs_dir_fromle32(struct lfs_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 lfs_dir_tole32(struct lfs_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 lfs_entry_fromle32(struct lfs_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 lfs_entry_tole32(struct lfs_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 lfs_superblock_fromle32(struct lfs_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);
d->inline_size = lfs_fromle32(d->inline_size);
d->attrs_size = lfs_fromle32(d->attrs_size);
d->name_size = lfs_fromle32(d->name_size);
}
static void lfs_superblock_tole32(struct lfs_disk_superblock *d) {
d->root[0] = lfs_tole32(d->root[0]);
d->root[1] = lfs_tole32(d->root[1]);
d->block_size = lfs_tole32(d->block_size);
d->block_count = lfs_tole32(d->block_count);
d->version = lfs_tole32(d->version);
d->inline_size = lfs_tole32(d->inline_size);
d->attrs_size = lfs_tole32(d->attrs_size);
d->name_size = lfs_tole32(d->name_size);
}
/// Other struct functions ///
static inline lfs_size_t lfs_entry_elen(const lfs_entry_t *entry) {
return (lfs_size_t)(entry->d.elen) |
((lfs_size_t)(entry->d.alen & 0xc0) << 2);
}
static inline lfs_size_t lfs_entry_alen(const lfs_entry_t *entry) {
return entry->d.alen & 0x3f;
}
static inline lfs_size_t lfs_entry_nlen(const lfs_entry_t *entry) {
return entry->d.nlen;
}
static inline lfs_size_t lfs_entry_size(const lfs_entry_t *entry) {
return 4 + lfs_entry_elen(entry) +
lfs_entry_alen(entry) +
lfs_entry_nlen(entry);
}
/// Metadata pair and directory operations ///
static inline void lfs_pairswap(lfs_block_t pair[2]) {
lfs_block_t t = pair[0];
pair[0] = pair[1];
pair[1] = t;
}
static inline bool lfs_pairisnull(const lfs_block_t pair[2]) {
return pair[0] == 0xffffffff || pair[1] == 0xffffffff;
}
static inline int lfs_paircmp(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return !(paira[0] == pairb[0] || paira[1] == pairb[1] ||
paira[0] == pairb[1] || paira[1] == pairb[0]);
}
static inline bool lfs_pairsync(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return (paira[0] == pairb[0] && paira[1] == pairb[1]) ||
(paira[0] == pairb[1] && paira[1] == pairb[0]);
}
static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
// allocate pair of dir blocks
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &dir->pair[i]);
if (err) {
return err;
}
}
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->d.rev, 4);
dir->d.rev = lfs_fromle32(dir->d.rev);
if (err) {
return err;
}
// set defaults
dir->d.rev += 1;
dir->d.size = sizeof(dir->d)+4;
dir->d.tail[0] = 0xffffffff;
dir->d.tail[1] = 0xffffffff;
dir->off = sizeof(dir->d);
// don't write out yet, let caller take care of that
return 0;
}
static int lfs_dir_fetch(lfs_t *lfs,
lfs_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 lfs_disk_dir test;
int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
lfs_dir_fromle32(&test);
if (err) {
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;
lfs_dir_tole32(&test);
lfs_crc(&crc, &test, sizeof(test));
lfs_dir_fromle32(&test);
err = lfs_bd_crc(lfs, tpair[i], sizeof(test),
(0x7fffffff & test.size) - sizeof(test), &crc);
if (err) {
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 %d %d", tpair[0], tpair[1]);
return LFS_ERR_CORRUPT;
}
return 0;
}
struct lfs_region {
enum {
LFS_FROM_MEM,
LFS_FROM_REGION,
LFS_FROM_ATTRS,
} type;
lfs_off_t oldoff;
lfs_size_t oldsize;
const void *buffer;
lfs_size_t newsize;
};
struct lfs_region_attrs {
const struct lfs_attr *attrs;
int count;
};
struct lfs_region_region {
lfs_block_t block;
lfs_off_t off;
struct lfs_region *regions;
int count;
};
static int lfs_commit_region(lfs_t *lfs, uint32_t *crc,
lfs_block_t oldblock, lfs_off_t oldoff,
lfs_block_t newblock, lfs_off_t newoff,
lfs_off_t regionoff, lfs_size_t regionsize,
const struct lfs_region *regions, int count) {
int i = 0;
lfs_size_t newend = newoff + regionsize;
while (newoff < newend) {
// commit from different types of regions
if (i < count && regions[i].oldoff == oldoff - regionoff) {
switch (regions[i].type) {
case LFS_FROM_MEM: {
lfs_crc(crc, regions[i].buffer, regions[i].newsize);
int err = lfs_bd_prog(lfs, newblock, newoff,
regions[i].buffer, regions[i].newsize);
if (err) {
return err;
}
newoff += regions[i].newsize;
oldoff += regions[i].oldsize;
break;
}
case LFS_FROM_REGION: {
const struct lfs_region_region *disk = regions[i].buffer;
int err = lfs_commit_region(lfs, crc,
disk->block, disk->off,
newblock, newoff,
disk->off, regions[i].newsize,
disk->regions, disk->count);
if (err) {
return err;
}
newoff += regions[i].newsize;
oldoff -= regions[i].oldsize;
break;
}
case LFS_FROM_ATTRS: {
const struct lfs_region_attrs *attrs = regions[i].buffer;
// order doesn't matter, so we write new attrs first. this
// is still O(n^2) but only O(n) disk access
for (int j = 0; j < attrs->count; j++) {
if (attrs->attrs[j].size == 0) {
continue;
}
lfs_entry_attr_t attr;
attr.d.type = attrs->attrs[j].type;
attr.d.len = attrs->attrs[j].size;
lfs_crc(crc, &attr.d, sizeof(attr.d));
int err = lfs_bd_prog(lfs, newblock, newoff,
&attr.d, sizeof(attr.d));
if (err) {
return err;
}
lfs_crc(crc,
attrs->attrs[j].buffer, attrs->attrs[j].size);
err = lfs_bd_prog(lfs, newblock, newoff+sizeof(attr.d),
attrs->attrs[j].buffer, attrs->attrs[j].size);
if (err) {
return err;
}
newoff += 2+attrs->attrs[j].size;
}
// copy over attributes without updates
lfs_off_t oldend = oldoff + regions[i].oldsize;
while (oldoff < oldend) {
lfs_entry_attr_t attr;
int err = lfs_bd_read(lfs, oldblock, oldoff,
&attr.d, sizeof(attr.d));
if (err) {
return err;
}
bool updating = false;
for (int j = 0; j < attrs->count; j++) {
if (attr.d.type == attrs->attrs[j].type) {
updating = true;
}
}
if (!updating) {
err = lfs_commit_region(lfs, crc,
oldblock, oldoff,
newblock, newoff,
0, 2+attr.d.len,
NULL, 0);
if (err) {
return err;
}
newoff += 2+attr.d.len;
}
oldoff += 2+attr.d.len;
}
break;
}
}
i += 1;
} else {
// copy data from old block if not covered by region
uint8_t data;
int err = lfs_bd_read(lfs, oldblock, oldoff, &data, 1);
if (err) {
return err;
}
lfs_crc(crc, &data, 1);
err = lfs_bd_prog(lfs, newblock, newoff, &data, 1);
if (err) {
return err;
}
oldoff += 1;
newoff += 1;
}
}
// sanity check our commit math
LFS_ASSERT(newoff == newend);
return 0;
}
static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
const struct lfs_region *regions, int count) {
// state for copying over
const lfs_block_t oldpair[2] = {dir->pair[1], dir->pair[0]};
bool relocated = false;
// increment revision count
dir->d.rev += 1;
// keep pairs in order such that pair[0] is most recent
lfs_pairswap(dir->pair);
for (int i = 0; i < count; i++) {
dir->d.size += regions[i].newsize;
dir->d.size -= regions[i].oldsize;
}
while (true) {
if (true) {
int err = lfs_bd_erase(lfs, dir->pair[0]);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// commit header
uint32_t crc = 0xffffffff;
lfs_dir_tole32(&dir->d);
lfs_crc(&crc, &dir->d, sizeof(dir->d));
err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
lfs_dir_fromle32(&dir->d);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// commit region
err = lfs_commit_region(lfs, &crc,
dir->pair[1], sizeof(dir->d),
dir->pair[0], sizeof(dir->d),
0, (0x7fffffff & dir->d.size)-sizeof(dir->d)-4,
regions, count);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// commit crc
crc = lfs_tole32(crc);
err = lfs_bd_prog(lfs, dir->pair[0],
(0x7fffffff & dir->d.size)-4, &crc, 4);
crc = lfs_fromle32(crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
err = lfs_bd_sync(lfs);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// successful commit, check checksum to make sure
uint32_t ncrc = 0xffffffff;
err = lfs_bd_crc(lfs, dir->pair[0], 0,
(0x7fffffff & dir->d.size)-4, &ncrc);
if (err) {
return err;
}
if (ncrc != crc) {
goto relocate;
}
}
break;
relocate:
//commit was corrupted
LFS_DEBUG("Bad block at %d", dir->pair[0]);
// drop caches and prepare to relocate block
relocated = true;
lfs->pcache.block = 0xffffffff;
// can't relocate superblock, filesystem is now frozen
if (lfs_paircmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
LFS_WARN("Superblock %d has become unwritable", oldpair[0]);
return LFS_ERR_CORRUPT;
}
// relocate half of pair
int err = lfs_alloc(lfs, &dir->pair[0]);
if (err) {
return err;
}
}
if (relocated) {
// update references if we relocated
LFS_DEBUG("Relocating %d %d to %d %d",
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
int err = lfs_relocate(lfs, oldpair, dir->pair);
if (err) {
return err;
}
}
// shift over any directories that are affected
for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
d->pair[0] = dir->pair[0];
d->pair[1] = dir->pair[1];
}
}
return 0;
}
static int lfs_dir_get(lfs_t *lfs, const lfs_dir_t *dir,
lfs_off_t off, void *buffer, lfs_size_t size) {
return lfs_bd_read(lfs, dir->pair[0], off, buffer, size);
}
static int lfs_dir_set(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry,
struct lfs_region *regions, int count) {
lfs_ssize_t diff = 0;
for (int i = 0; i < count; i++) {
diff += regions[i].newsize;
diff -= regions[i].oldsize;
}
lfs_size_t oldsize = entry->size;
if (entry->off == 0) {
entry->off = (0x7fffffff & dir->d.size) - 4;
}
if ((0x7fffffff & dir->d.size) + diff > lfs->cfg->block_size) {
lfs_dir_t olddir = *dir;
lfs_off_t oldoff = entry->off;
if (oldsize) {
// mark as moving
uint8_t type;
int err = lfs_dir_get(lfs, &olddir, oldoff, &type, 1);
if (err) {
return err;
}
type |= LFS_STRUCT_MOVED;
err = lfs_dir_commit(lfs, &olddir, (struct lfs_region[]){
{LFS_FROM_MEM, oldoff, 1, &type, 1}}, 1);
if (err) {
return err;
}
}
lfs_dir_t pdir = olddir;
// find available block or create a new one
while ((0x7fffffff & dir->d.size) + oldsize + diff
> lfs->cfg->block_size) {
// we need to allocate a new dir block
if (!(0x80000000 & dir->d.size)) {
pdir = *dir;
int err = lfs_dir_alloc(lfs, dir);
if (err) {
return err;
}
dir->d.tail[0] = pdir.d.tail[0];
dir->d.tail[1] = pdir.d.tail[1];
break;
}
int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
}
// writing out new entry
entry->off = dir->d.size - 4;
entry->size += diff;
int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
{LFS_FROM_REGION, entry->off, 0, &(struct lfs_region_region){
olddir.pair[0], oldoff,
regions, count}, entry->size}}, 1);
if (err) {
return err;
}
// update pred dir, unless pred == old we can coalesce
if (!oldsize || lfs_paircmp(pdir.pair, olddir.pair) != 0) {
pdir.d.size |= 0x80000000;
pdir.d.tail[0] = dir->pair[0];
pdir.d.tail[1] = dir->pair[1];
err = lfs_dir_commit(lfs, &pdir, NULL, 0);
if (err) {
return err;
}
} else if (oldsize) {
olddir.d.size |= 0x80000000;
olddir.d.tail[0] = dir->pair[0];
olddir.d.tail[1] = dir->pair[1];
}
// remove old entry
if (oldsize) {
lfs_entry_t oldentry;
oldentry.off = oldoff;
err = lfs_dir_set(lfs, &olddir, &oldentry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, oldsize, NULL, 0}}, 1);
if (err) {
return err;
}
}
goto shift;
}
if ((0x7fffffff & dir->d.size) + diff == sizeof(dir->d)+4) {
lfs_dir_t pdir;
int res = lfs_pred(lfs, dir->pair, &pdir);
if (res < 0) {
return res;
}
if (pdir.d.size & 0x80000000) {
pdir.d.size &= dir->d.size | 0x7fffffff;
pdir.d.tail[0] = dir->d.tail[0];
pdir.d.tail[1] = dir->d.tail[1];
int err = lfs_dir_commit(lfs, &pdir, NULL, 0);
if (err) {
return err;
}
goto shift;
}
}
for (int i = 0; i < count; i++) {
regions[i].oldoff += entry->off;
}
int err = lfs_dir_commit(lfs, dir, regions, count);
if (err) {
return err;
}
entry->size += diff;
shift:
// shift over any files/directories that are affected
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (lfs_paircmp(f->pair, dir->pair) == 0) {
if (f->pairoff == entry->off && entry->size == 0) {
f->pair[0] = 0xffffffff;
f->pair[1] = 0xffffffff;
} else if (f->pairoff > entry->off) {
f->pairoff += diff;
}
}
}
for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
if (lfs_paircmp(d->pair, dir->pair) == 0) {
if (d->off > entry->off) {
d->off += diff;
d->pos += diff;
}
}
}
return 0;
}
static int lfs_dir_next(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
while (dir->off >= (0x7fffffff & dir->d.size)-4) {
if (!(0x80000000 & dir->d.size)) {
entry->off = dir->off;
return LFS_ERR_NOENT;
}
int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
dir->off = sizeof(dir->d);
dir->pos += sizeof(dir->d) + 4;
}
int err = lfs_dir_get(lfs, dir, dir->off, &entry->d, sizeof(entry->d));
lfs_entry_fromle32(&entry->d);
if (err) {
return err;
}
entry->off = dir->off;
entry->size = lfs_entry_size(entry);
dir->off += entry->size;
dir->pos += entry->size;
return 0;
}
static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, const char **path) {
const char *pathname = *path;
lfs_size_t pathlen;
while (true) {
nextname:
// skip slashes
pathname += strspn(pathname, "/");
pathlen = strcspn(pathname, "/");
// special case for root dir
if (pathname[0] == '\0') {
*entry = (lfs_entry_t){
.d.type = LFS_STRUCT_DIR | LFS_TYPE_DIR,
.d.u.dir[0] = lfs->root[0],
.d.u.dir[1] = lfs->root[1],
};
return 0;
}
// skip '.' and root '..'
if ((pathlen == 1 && memcmp(pathname, ".", 1) == 0) ||
(pathlen == 2 && memcmp(pathname, "..", 2) == 0)) {
pathname += pathlen;
goto nextname;
}
// skip if matched by '..' in name
const char *suffix = pathname + pathlen;
lfs_size_t sufflen;
int depth = 1;
while (true) {
suffix += strspn(suffix, "/");
sufflen = strcspn(suffix, "/");
if (sufflen == 0) {
break;
}
if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
pathname = suffix + sufflen;
goto nextname;
}
} else {
depth += 1;
}
suffix += sufflen;
}
// update what we've found
*path = pathname;
// find path
while (true) {
int err = lfs_dir_next(lfs, dir, entry);
if (err) {
return err;
}
if (((0xf & entry->d.type) != LFS_TYPE_REG &&
(0xf & entry->d.type) != LFS_TYPE_DIR) ||
entry->d.nlen != pathlen) {
continue;
}
int res = lfs_bd_cmp(lfs, dir->pair[0],
entry->off + entry->size - pathlen,
pathname, pathlen);
if (res < 0) {
return res;
}
// found match
if (res) {
break;
}
}
// check that entry has not been moved
if (entry->d.type & LFS_STRUCT_MOVED) {
int moved = lfs_moved(lfs, &entry->d.u);
if (moved < 0 || moved) {
return (moved < 0) ? moved : LFS_ERR_NOENT;
}
entry->d.type &= ~LFS_STRUCT_MOVED;
}
pathname += pathlen;
pathname += strspn(pathname, "/");
if (pathname[0] == '\0') {
return 0;
}
// continue on if we hit a directory
if ((0xf & entry->d.type) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
if (err) {
return err;
}
}
}
/// Internal attribute operations ///
static int lfs_dir_getinfo(lfs_t *lfs,
lfs_dir_t *dir, const lfs_entry_t *entry, struct lfs_info *info) {
memset(info, 0, sizeof(*info));
info->type = 0xf & entry->d.type;
if (entry->d.type == (LFS_STRUCT_CTZ | LFS_TYPE_REG)) {
info->size = entry->d.u.file.size;
} else if (entry->d.type == (LFS_STRUCT_INLINE | LFS_TYPE_REG)) {
info->size = lfs_entry_elen(entry);
}
if (lfs_paircmp(entry->d.u.dir, lfs->root) == 0) {
strcpy(info->name, "/");
} else {
int err = lfs_dir_get(lfs, dir,
entry->off + entry->size - entry->d.nlen,
info->name, entry->d.nlen);
if (err) {
return err;
}
}
return 0;
}
static int lfs_dir_getattrs(lfs_t *lfs,
lfs_dir_t *dir, const lfs_entry_t *entry,
const struct lfs_attr *attrs, int count) {
// set to zero in case we can't find the attributes or size mismatch
for (int j = 0; j < count; j++) {
memset(attrs[j].buffer, 0, attrs[j].size);
}
// search for attribute in attribute region
lfs_off_t off = entry->off + 4+lfs_entry_elen(entry);
lfs_off_t end = off + lfs_entry_alen(entry);
while (off < end) {
lfs_entry_attr_t attr;
int err = lfs_dir_get(lfs, dir, off, &attr.d, sizeof(attr.d));
if (err) {
return err;
}
for (int j = 0; j < count; j++) {
if (attrs[j].type == attr.d.type) {
if (attrs[j].size < attr.d.len) {
return LFS_ERR_RANGE;
}
err = lfs_dir_get(lfs, dir, off+sizeof(attr.d),
attrs[j].buffer, attr.d.len);
if (err) {
return err;
}
}
}
off += 2+attr.d.len;
}
return 0;
}
static lfs_ssize_t lfs_dir_checkattrs(lfs_t *lfs,
lfs_dir_t *dir, lfs_entry_t *entry,
const struct lfs_attr *attrs, int count) {
// check that attributes fit
// two separate passes so disk access is O(n)
lfs_size_t nsize = 0;
for (int j = 0; j < count; j++) {
if (attrs[j].size > 0) {
nsize += 2+attrs[j].size;
}
}
lfs_off_t off = entry->off + 4+lfs_entry_elen(entry);
lfs_off_t end = off + lfs_entry_alen(entry);
while (off < end) {
lfs_entry_attr_t attr;
int err = lfs_dir_get(lfs, dir, off, &attr.d, sizeof(attr.d));
if (err) {
return err;
}
bool updated = false;
for (int j = 0; j < count; j++) {
if (attr.d.type == attrs[j].type) {
updated = true;
}
}
if (!updated) {
nsize += 2+attr.d.len;
}
off += 2+attr.d.len;
}
if (nsize > lfs->attrs_size || (
lfs_entry_size(entry) - lfs_entry_alen(entry) + nsize
> lfs->cfg->block_size)) {
return LFS_ERR_NOSPC;
}
return nsize;
}
static int lfs_dir_setattrs(lfs_t *lfs,
lfs_dir_t *dir, lfs_entry_t *entry,
const struct lfs_attr *attrs, int count) {
// make sure attributes fit
lfs_size_t oldlen = lfs_entry_alen(entry);
lfs_ssize_t newlen = lfs_dir_checkattrs(lfs, dir, entry, attrs, count);
if (newlen < 0) {
return newlen;
}
// commit to entry, majority of work is in LFS_FROM_ATTRS
entry->d.alen = (0xc0 & entry->d.alen) | newlen;
return lfs_dir_set(lfs, dir, entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 4, &entry->d, 4},
{LFS_FROM_ATTRS, 4+lfs_entry_elen(entry), oldlen,
&(struct lfs_region_attrs){attrs, count}, newlen}}, 2);
}
/// Top level directory operations ///
int lfs_mkdir(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
if (!lfs->deorphaned) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
// fetch parent directory
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err != LFS_ERR_NOENT || strchr(path, '/') != NULL) {
return err ? err : LFS_ERR_EXIST;
}
// check that name fits
lfs_size_t nlen = strlen(path);
if (nlen > lfs->name_size) {
return LFS_ERR_NAMETOOLONG;
}
// build up new directory
lfs_alloc_ack(lfs);
lfs_dir_t dir;
err = lfs_dir_alloc(lfs, &dir);
if (err) {
return err;
}
dir.d.tail[0] = cwd.d.tail[0];
dir.d.tail[1] = cwd.d.tail[1];
err = lfs_dir_commit(lfs, &dir, NULL, 0);
if (err) {
return err;
}
entry.d.type = LFS_STRUCT_DIR | LFS_TYPE_DIR;
entry.d.elen = sizeof(entry.d) - 4;
entry.d.alen = 0;
entry.d.nlen = nlen;
entry.d.u.dir[0] = dir.pair[0];
entry.d.u.dir[1] = dir.pair[1];
entry.size = 0;
cwd.d.tail[0] = dir.pair[0];
cwd.d.tail[1] = dir.pair[1];
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 0, &entry.d, sizeof(entry.d)},
{LFS_FROM_MEM, 0, 0, path, nlen}}, 2);
if (err) {
return err;
}
lfs_alloc_ack(lfs);
return 0;
}
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
dir->pair[0] = lfs->root[0];
dir->pair[1] = lfs->root[1];
int err = lfs_dir_fetch(lfs, dir, dir->pair);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, dir, &entry, &path);
if (err) {
return err;
} else if (entry.d.type != (LFS_STRUCT_DIR | LFS_TYPE_DIR)) {
return LFS_ERR_NOTDIR;
}
err = lfs_dir_fetch(lfs, dir, entry.d.u.dir);
if (err) {
return err;
}
// setup head dir
// special offset for '.' and '..'
dir->head[0] = dir->pair[0];
dir->head[1] = dir->pair[1];
dir->pos = sizeof(dir->d) - 2;
dir->off = sizeof(dir->d);
// add to list of directories
dir->next = lfs->dirs;
lfs->dirs = dir;
return 0;
}
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
// remove from list of directories
for (lfs_dir_t **p = &lfs->dirs; *p; p = &(*p)->next) {
if (*p == dir) {
*p = dir->next;
break;
}
}
return 0;
}
int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info) {
memset(info, 0, sizeof(*info));
// special offset for '.' and '..'
if (dir->pos == sizeof(dir->d) - 2) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, ".");
dir->pos += 1;
return 1;
} else if (dir->pos == sizeof(dir->d) - 1) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, "..");
dir->pos += 1;
return 1;
}
lfs_entry_t entry;
while (true) {
int err = lfs_dir_next(lfs, dir, &entry);
if (err) {
return (err == LFS_ERR_NOENT) ? 0 : err;
}
if ((0xf & entry.d.type) != LFS_TYPE_REG &&
(0xf & entry.d.type) != LFS_TYPE_DIR) {
continue;
}
// check that entry has not been moved
if (entry.d.type & LFS_STRUCT_MOVED) {
int moved = lfs_moved(lfs, &entry.d.u);
if (moved < 0) {
return moved;
}
if (moved) {
continue;
}
entry.d.type &= ~LFS_STRUCT_MOVED;
}
break;
}
int err = lfs_dir_getinfo(lfs, dir, &entry, info);
if (err) {
return err;
}
return 1;
}
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
// simply walk from head dir
int err = lfs_dir_rewind(lfs, dir);
if (err) {
return err;
}
dir->pos = off;
while (off > (0x7fffffff & dir->d.size)) {
off -= 0x7fffffff & dir->d.size;
if (!(0x80000000 & dir->d.size)) {
return LFS_ERR_INVAL;
}
err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
}
dir->off = off;
return 0;
}
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir) {
(void)lfs;
return dir->pos;
}
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir) {
// reload the head dir
int err = lfs_dir_fetch(lfs, dir, dir->head);
if (err) {
return err;
}
dir->pair[0] = dir->head[0];
dir->pair[1] = dir->head[1];
dir->pos = sizeof(dir->d) - 2;
dir->off = sizeof(dir->d);
return 0;
}
/// File index list operations ///
static int lfs_ctz_index(lfs_t *lfs, lfs_off_t *off) {
lfs_off_t size = *off;
lfs_off_t b = lfs->cfg->block_size - 2*4;
lfs_off_t i = size / b;
if (i == 0) {
return 0;
}
i = (size - 4*(lfs_popc(i-1)+2)) / b;
*off = size - b*i - 4*lfs_popc(i);
return i;
}
static int lfs_ctz_find(lfs_t *lfs,
lfs_cache_t *rcache, const lfs_cache_t *pcache,
lfs_block_t head, lfs_size_t size,
lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
if (size == 0) {
*block = 0xffffffff;
*off = 0;
return 0;
}
lfs_off_t current = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
lfs_off_t target = lfs_ctz_index(lfs, &pos);
while (current > target) {
lfs_size_t skip = lfs_min(
lfs_npw2(current-target+1) - 1,
lfs_ctz(current));
int err = lfs_cache_read(lfs, rcache, pcache, head, 4*skip, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
current -= 1 << skip;
}
*block = head;
*off = pos;
return 0;
}
static int lfs_ctz_extend(lfs_t *lfs,
lfs_cache_t *rcache, lfs_cache_t *pcache,
lfs_block_t head, lfs_size_t size,
lfs_block_t *block, lfs_off_t *off) {
while (true) {
// go ahead and grab a block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
if (true) {
err = lfs_bd_erase(lfs, nblock);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (size == 0) {
*block = nblock;
*off = 0;
return 0;
}
size -= 1;
lfs_off_t index = lfs_ctz_index(lfs, &size);
size += 1;
// just copy out the last block if it is incomplete
if (size != lfs->cfg->block_size) {
for (lfs_off_t i = 0; i < size; i++) {
uint8_t data;
err = lfs_cache_read(lfs, rcache, NULL,
head, i, &data, 1);
if (err) {
return err;
}
err = lfs_cache_prog(lfs, pcache, rcache,
nblock, i, &data, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
*block = nblock;
*off = size;
return 0;
}
// append block
index += 1;
lfs_size_t skips = lfs_ctz(index) + 1;
for (lfs_off_t i = 0; i < skips; i++) {
head = lfs_tole32(head);
err = lfs_cache_prog(lfs, pcache, rcache,
nblock, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (i != skips-1) {
err = lfs_cache_read(lfs, rcache, NULL,
head, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
}
*block = nblock;
*off = 4*skips;
return 0;
}
relocate:
LFS_DEBUG("Bad block at %d", nblock);
// just clear cache and try a new block
pcache->block = 0xffffffff;
}
}
static int lfs_ctz_traverse(lfs_t *lfs,
lfs_cache_t *rcache, const lfs_cache_t *pcache,
lfs_block_t head, lfs_size_t size,
int (*cb)(void*, lfs_block_t), void *data) {
if (size == 0) {
return 0;
}
lfs_off_t index = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
while (true) {
int err = cb(data, head);
if (err) {
return err;
}
if (index == 0) {
return 0;
}
lfs_block_t heads[2];
int count = 2 - (index & 1);
err = lfs_cache_read(lfs, rcache, pcache, head, 0, &heads, count*4);
heads[0] = lfs_fromle32(heads[0]);
heads[1] = lfs_fromle32(heads[1]);
if (err) {
return err;
}
for (int i = 0; i < count-1; i++) {
err = cb(data, heads[i]);
if (err) {
return err;
}
}
head = heads[count-1];
index -= count;
}
}
/// Top level file operations ///
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags) {
// deorphan if we haven't yet, needed at most once after poweron
if ((flags & 3) != LFS_O_RDONLY && !lfs->deorphaned) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
// allocate entry for file if it doesn't exist
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err && (err != LFS_ERR_NOENT || strchr(path, '/') != NULL)) {
return err;
}
if (err == LFS_ERR_NOENT) {
if (!(flags & LFS_O_CREAT)) {
return LFS_ERR_NOENT;
}
// check that name fits
lfs_size_t nlen = strlen(path);
if (nlen > lfs->name_size) {
return LFS_ERR_NAMETOOLONG;
}
// create entry to remember name
entry.d.type = LFS_STRUCT_INLINE | LFS_TYPE_REG;
entry.d.elen = 0;
entry.d.alen = 0;
entry.d.nlen = nlen;
entry.size = 0;
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 0, &entry.d, 4},
{LFS_FROM_MEM, 0, 0, path, nlen}}, 2);
if (err) {
return err;
}
} else if ((0xf & entry.d.type) == LFS_TYPE_DIR) {
return LFS_ERR_ISDIR;
} else if (flags & LFS_O_EXCL) {
return LFS_ERR_EXIST;
}
// allocate buffer if needed
file->cache.block = 0xffffffff;
if (lfs->cfg->file_buffer) {
file->cache.buffer = lfs->cfg->file_buffer;
} else if ((file->flags & 3) == LFS_O_RDONLY) {
file->cache.buffer = lfs_malloc(lfs->cfg->read_size);
if (!file->cache.buffer) {
return LFS_ERR_NOMEM;
}
} else {
file->cache.buffer = lfs_malloc(lfs->cfg->prog_size);
if (!file->cache.buffer) {
return LFS_ERR_NOMEM;
}
}
// setup file struct
file->pair[0] = cwd.pair[0];
file->pair[1] = cwd.pair[1];
file->pairoff = entry.off;
file->flags = flags;
file->pos = 0;
// calculate max inline size based on the size of the entry
file->inline_size = lfs_min(lfs->inline_size,
lfs->cfg->block_size - (sizeof(cwd.d)+4) -
(lfs_entry_size(&entry) - lfs_entry_elen(&entry)));
if ((0x70 & entry.d.type) == LFS_STRUCT_INLINE) {
// load inline files
file->head = 0xfffffffe;
file->size = lfs_entry_elen(&entry);
file->flags |= LFS_F_INLINE;
file->cache.block = file->head;
file->cache.off = 0;
err = lfs_dir_get(lfs, &cwd,
entry.off + 4,
file->cache.buffer, file->size);
if (err) {
lfs_free(file->cache.buffer);
return err;
}
} else {
// use ctz list from entry
file->head = entry.d.u.file.head;
file->size = entry.d.u.file.size;
}
// truncate if requested
if (flags & LFS_O_TRUNC) {
if (file->size != 0) {
file->flags |= LFS_F_DIRTY;
}
file->head = 0xfffffffe;
file->size = 0;
file->flags |= LFS_F_INLINE;
file->cache.block = file->head;
file->cache.off = 0;
}
// add to list of files
file->next = lfs->files;
lfs->files = file;
return 0;
}
int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_sync(lfs, file);
// remove from list of files
for (lfs_file_t **p = &lfs->files; *p; p = &(*p)->next) {
if (*p == file) {
*p = file->next;
break;
}
}
// clean up memory
if (!lfs->cfg->file_buffer) {
lfs_free(file->cache.buffer);
}
return err;
}
static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
relocate:;
// just relocate what exists into new block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
err = lfs_bd_erase(lfs, nblock);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// either read from dirty cache or disk
for (lfs_off_t i = 0; i < file->off; i++) {
uint8_t data;
err = lfs_cache_read(lfs, &lfs->rcache, &file->cache,
file->block, i, &data, 1);
if (err) {
return err;
}
err = lfs_cache_prog(lfs, &lfs->pcache, &lfs->rcache,
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->prog_size);
file->cache.block = lfs->pcache.block;
file->cache.off = lfs->pcache.off;
lfs->pcache.block = 0xffffffff;
file->block = nblock;
return 0;
}
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
if (file->flags & LFS_F_READING) {
file->flags &= ~LFS_F_READING;
}
if (file->flags & LFS_F_WRITING) {
lfs_off_t pos = file->pos;
if (!(file->flags & LFS_F_INLINE)) {
// copy over anything after current branch
lfs_file_t orig = {
.head = file->head,
.size = file->size,
.flags = LFS_O_RDONLY,
.pos = file->pos,
.cache = lfs->rcache,
};
lfs->rcache.block = 0xffffffff;
while (file->pos < file->size) {
// copy over a byte at a time, leave it up to caching
// to make this efficient
uint8_t data;
lfs_ssize_t res = lfs_file_read(lfs, &orig, &data, 1);
if (res < 0) {
return res;
}
res = lfs_file_write(lfs, file, &data, 1);
if (res < 0) {
return res;
}
// keep our reference to the rcache in sync
if (lfs->rcache.block != 0xffffffff) {
orig.cache.block = 0xffffffff;
lfs->rcache.block = 0xffffffff;
}
}
// write out what we have
while (true) {
int err = lfs_cache_flush(lfs, &file->cache, &lfs->rcache);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
break;
relocate:
LFS_DEBUG("Bad block at %d", file->block);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
}
} else {
file->size = lfs_max(file->pos, file->size);
}
// actual file updates
file->head = file->block;
file->size = file->pos;
file->flags &= ~LFS_F_WRITING;
file->flags |= LFS_F_DIRTY;
file->pos = pos;
}
return 0;
}
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
if ((file->flags & LFS_F_DIRTY) &&
!(file->flags & LFS_F_ERRED) &&
!lfs_pairisnull(file->pair)) {
// update dir entry
lfs_dir_t cwd;
err = lfs_dir_fetch(lfs, &cwd, file->pair);
if (err) {
return err;
}
lfs_entry_t entry = {.off = file->pairoff};
err = lfs_dir_get(lfs, &cwd, entry.off, &entry.d, sizeof(entry.d));
lfs_entry_fromle32(&entry.d);
if (err) {
return err;
}
entry.size = lfs_entry_size(&entry);
LFS_ASSERT((0xf & entry.d.type) == LFS_TYPE_REG);
lfs_size_t oldelen = lfs_entry_elen(&entry);
lfs_size_t oldalen = lfs_entry_alen(&entry);
const void *buffer;
lfs_size_t size;
// either update the references or inline the whole file
if (!(file->flags & LFS_F_INLINE)) {
entry.d.type = LFS_STRUCT_CTZ | LFS_TYPE_REG;
entry.d.u.file.head = file->head;
entry.d.u.file.size = file->size;
buffer = (const uint8_t *)&entry.d + 4;
size = sizeof(entry.d) - 4;
} else {
entry.d.type = LFS_STRUCT_INLINE | LFS_TYPE_REG;
buffer = file->cache.buffer;
size = file->size;
}
// get new alen from disk
lfs_ssize_t newalen = lfs_dir_checkattrs(lfs, &cwd, &entry,
file->attrs, file->attrcount);
if (newalen < 0) {
return newalen;
}
entry.d.elen = size & 0xff;
entry.d.alen = (newalen & 0x3f) | ((size >> 2) & 0xc0);
// write out update
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 4, &entry.d, 4},
{LFS_FROM_MEM, 4, oldelen, buffer, size},
{LFS_FROM_ATTRS, 4+oldelen, oldalen,
&(struct lfs_region_attrs){file->attrs, file->attrcount},
newalen}}, 3);
if (err) {
return err;
}
file->flags &= ~LFS_F_DIRTY;
}
return 0;
}
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_WRONLY) {
return LFS_ERR_BADF;
}
if (file->flags & LFS_F_WRITING) {
// flush out any writes
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if (file->pos >= file->size) {
// eof if past end
return 0;
}
size = lfs_min(size, file->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, &file->cache, NULL,
file->head, file->size,
file->pos, &file->block, &file->off);
if (err) {
return err;
}
} else {
file->block = 0xfffffffe;
file->off = file->pos;
}
file->flags |= LFS_F_READING;
}
// read as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
int err = lfs_cache_read(lfs, &file->cache, NULL,
file->block, file->off, data, diff);
if (err) {
return err;
}
file->pos += diff;
file->off += diff;
data += diff;
nsize -= diff;
}
return size;
}
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
if (file->flags & LFS_F_READING) {
// drop any reads
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if ((file->flags & LFS_O_APPEND) && file->pos < file->size) {
file->pos = file->size;
}
if (!(file->flags & LFS_F_WRITING) && file->pos > file->size) {
// fill with zeros
lfs_off_t pos = file->pos;
file->pos = file->size;
while (file->pos < pos) {
lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
}
if ((file->flags & LFS_F_INLINE) &&
file->pos + nsize >= file->inline_size) {
// inline file doesn't fit anymore
file->block = 0xfffffffe;
file->off = file->pos;
lfs_alloc_ack(lfs);
int err = lfs_file_relocate(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
file->flags &= ~LFS_F_INLINE;
file->flags |= LFS_F_WRITING;
}
while (nsize > 0) {
// check if we need a new block
if (!(file->flags & LFS_F_WRITING) ||
file->off == lfs->cfg->block_size) {
if (!(file->flags & LFS_F_INLINE)) {
if (!(file->flags & LFS_F_WRITING) && file->pos > 0) {
// find out which block we're extending from
int err = lfs_ctz_find(lfs, &file->cache, NULL,
file->head, file->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
file->cache.block = 0xffffffff;
}
// extend file with new blocks
lfs_alloc_ack(lfs);
int err = lfs_ctz_extend(lfs, &lfs->rcache, &file->cache,
file->block, file->pos,
&file->block, &file->off);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
} else {
file->block = 0xfffffffe;
file->off = file->pos;
}
file->flags |= LFS_F_WRITING;
}
// program as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
while (true) {
int err = lfs_cache_prog(lfs, &file->cache, &lfs->rcache,
file->block, file->off, data, diff);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
file->flags |= LFS_F_ERRED;
return err;
}
break;
relocate:
err = lfs_file_relocate(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
}
file->pos += diff;
file->off += diff;
data += diff;
nsize -= diff;
lfs_alloc_ack(lfs);
}
file->flags &= ~LFS_F_ERRED;
return size;
}
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
// write out everything beforehand, may be noop if rdonly
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// update pos
if (whence == LFS_SEEK_SET) {
file->pos = off;
} else if (whence == LFS_SEEK_CUR) {
if (off < 0 && (lfs_off_t)-off > file->pos) {
return LFS_ERR_INVAL;
}
file->pos = file->pos + off;
} else if (whence == LFS_SEEK_END) {
if (off < 0 && (lfs_off_t)-off > file->size) {
return LFS_ERR_INVAL;
}
file->pos = file->size + off;
}
return file->pos;
}
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
lfs_off_t oldsize = lfs_file_size(lfs, file);
if (size < oldsize) {
// need to flush since directly changing metadata
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// lookup new head in ctz skip list
err = lfs_ctz_find(lfs, &file->cache, NULL,
file->head, file->size,
size, &file->head, &(lfs_off_t){0});
if (err) {
return err;
}
file->size = size;
file->flags |= LFS_F_DIRTY;
} else if (size > oldsize) {
lfs_off_t pos = file->pos;
// flush+seek if not already at end
if (file->pos != oldsize) {
int err = lfs_file_seek(lfs, file, 0, LFS_SEEK_END);
if (err < 0) {
return err;
}
}
// fill with zeros
while (file->pos < size) {
lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
// restore pos
int err = lfs_file_seek(lfs, file, pos, LFS_SEEK_SET);
if (err < 0) {
return err;
}
}
return 0;
}
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
return file->pos;
}
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file) {
lfs_soff_t res = lfs_file_seek(lfs, file, 0, LFS_SEEK_SET);
if (res < 0) {
return res;
}
return 0;
}
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
if (file->flags & LFS_F_WRITING) {
return lfs_max(file->pos, file->size);
} else {
return file->size;
}
}
int lfs_file_getattrs(lfs_t *lfs, lfs_file_t *file,
const struct lfs_attr *attrs, int count) {
// set to null in case we can't find the attrs (missing file?)
for (int j = 0; j < count; j++) {
memset(attrs[j].buffer, 0, attrs[j].size);
}
// load from disk if we haven't already been deleted
if (!lfs_pairisnull(file->pair)) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, file->pair);
if (err) {
return err;
}
lfs_entry_t entry = {.off = file->pairoff};
err = lfs_dir_get(lfs, &cwd, entry.off, &entry.d, sizeof(entry.d));
if (err) {
return err;
}
entry.size = lfs_entry_size(&entry);
err = lfs_dir_getattrs(lfs, &cwd, &entry, attrs, count);
if (err) {
return err;
}
}
// override an attrs we have stored locally
for (int i = 0; i < file->attrcount; i++) {
for (int j = 0; j < count; j++) {
if (attrs[j].type == file->attrs[i].type) {
if (attrs[j].size < file->attrs[i].size) {
return LFS_ERR_RANGE;
}
memcpy(attrs[j].buffer,
file->attrs[i].buffer, file->attrs[i].size);
}
}
}
return 0;
}
int lfs_file_setattrs(lfs_t *lfs, lfs_file_t *file,
const struct lfs_attr *attrs, int count) {
// just tack to the file, will be written at sync time
file->attrs = attrs;
file->attrcount = count;
// at least make sure attributes fit
if (!lfs_pairisnull(file->pair)) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, file->pair);
if (err) {
return err;
}
lfs_entry_t entry = {.off = file->pairoff};
err = lfs_dir_get(lfs, &cwd, entry.off, &entry.d, sizeof(entry.d));
if (err) {
return err;
}
entry.size = lfs_entry_size(&entry);
lfs_ssize_t res = lfs_dir_checkattrs(lfs, &cwd, &entry, attrs, count);
if (res < 0) {
return res;
}
}
return 0;
}
/// General fs operations ///
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
return lfs_dir_getinfo(lfs, &cwd, &entry, info);
}
int lfs_remove(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
if (!lfs->deorphaned) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
lfs_dir_t dir;
if ((0xf & entry.d.type) == LFS_TYPE_DIR) {
// must be empty before removal, checking size
// without masking top bit checks for any case where
// dir is not empty
err = lfs_dir_fetch(lfs, &dir, entry.d.u.dir);
if (err) {
return err;
} else if (dir.d.size != sizeof(dir.d)+4) {
return LFS_ERR_NOTEMPTY;
}
}
// remove the entry
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, entry.size, NULL, 0}}, 1);
if (err) {
return err;
}
// if we were a directory, find pred, replace tail
if ((0xf & entry.d.type) == LFS_TYPE_DIR) {
int res = lfs_pred(lfs, dir.pair, &cwd);
if (res < 0) {
return res;
}
LFS_ASSERT(res); // must have pred
cwd.d.tail[0] = dir.d.tail[0];
cwd.d.tail[1] = dir.d.tail[1];
err = lfs_dir_commit(lfs, &cwd, NULL, 0);
if (err) {
return err;
}
}
return 0;
}
int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
// deorphan if we haven't yet, needed at most once after poweron
if (!lfs->deorphaned) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
// find old entry
lfs_dir_t oldcwd;
int err = lfs_dir_fetch(lfs, &oldcwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t oldentry;
err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
if (err) {
return err;
}
// allocate new entry
lfs_dir_t newcwd;
err = lfs_dir_fetch(lfs, &newcwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t preventry;
err = lfs_dir_find(lfs, &newcwd, &preventry, &newpath);
if (err && (err != LFS_ERR_NOENT || strchr(newpath, '/') != NULL)) {
return err;
}
bool prevexists = (err != LFS_ERR_NOENT);
bool samepair = (lfs_paircmp(oldcwd.pair, newcwd.pair) == 0);
// check that name fits
lfs_size_t nlen = strlen(newpath);
if (nlen > lfs->name_size) {
return LFS_ERR_NAMETOOLONG;
}
// must have same type
if (prevexists && preventry.d.type != oldentry.d.type) {
return LFS_ERR_ISDIR;
}
lfs_dir_t dir;
if (prevexists && (0xf & preventry.d.type) == LFS_TYPE_DIR) {
// must be empty before removal, checking size
// without masking top bit checks for any case where
// dir is not empty
err = lfs_dir_fetch(lfs, &dir, preventry.d.u.dir);
if (err) {
return err;
} else if (dir.d.size != sizeof(dir.d)+4) {
return LFS_ERR_NOTEMPTY;
}
}
// mark as moving
oldentry.d.type |= LFS_STRUCT_MOVED;
err = lfs_dir_set(lfs, &oldcwd, &oldentry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 1, &oldentry.d.type, 1}}, 1);
oldentry.d.type &= ~LFS_STRUCT_MOVED;
if (err) {
return err;
}
// update pair if newcwd == oldcwd
if (samepair) {
newcwd = oldcwd;
}
// move to new location
lfs_entry_t newentry = preventry;
newentry.d = oldentry.d;
newentry.d.type &= ~LFS_STRUCT_MOVED;
newentry.d.nlen = nlen;
newentry.size = prevexists ? preventry.size : 0;
lfs_size_t newsize = oldentry.size - oldentry.d.nlen + newentry.d.nlen;
err = lfs_dir_set(lfs, &newcwd, &newentry, (struct lfs_region[]){
{LFS_FROM_REGION, 0, prevexists ? preventry.size : 0,
&(struct lfs_region_region){
oldcwd.pair[0], oldentry.off, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 4, &newentry.d, 4},
{LFS_FROM_MEM, newsize-nlen, 0, newpath, nlen}}, 2},
newsize}}, 1);
if (err) {
return err;
}
// update pair if newcwd == oldcwd
if (samepair) {
oldcwd = newcwd;
}
// remove old entry
err = lfs_dir_set(lfs, &oldcwd, &oldentry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, oldentry.size, NULL, 0}}, 1);
if (err) {
return err;
}
// if we were a directory, find pred, replace tail
if (prevexists && (0xf & preventry.d.type) == LFS_TYPE_DIR) {
int res = lfs_pred(lfs, dir.pair, &newcwd);
if (res < 0) {
return res;
}
LFS_ASSERT(res); // must have pred
newcwd.d.tail[0] = dir.d.tail[0];
newcwd.d.tail[1] = dir.d.tail[1];
err = lfs_dir_commit(lfs, &newcwd, NULL, 0);
if (err) {
return err;
}
}
return 0;
}
int lfs_getattrs(lfs_t *lfs, const char *path,
const struct lfs_attr *attrs, int count) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
return lfs_dir_getattrs(lfs, &cwd, &entry, attrs, count);
}
int lfs_setattrs(lfs_t *lfs, const char *path,
const struct lfs_attr *attrs, int count) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
return lfs_dir_setattrs(lfs, &cwd, &entry, attrs, count);
}
/// Filesystem operations ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
lfs->cfg = cfg;
// setup read cache
lfs->rcache.block = 0xffffffff;
if (lfs->cfg->read_buffer) {
lfs->rcache.buffer = lfs->cfg->read_buffer;
} else {
lfs->rcache.buffer = lfs_malloc(lfs->cfg->read_size);
if (!lfs->rcache.buffer) {
return LFS_ERR_NOMEM;
}
}
// setup program cache
lfs->pcache.block = 0xffffffff;
if (lfs->cfg->prog_buffer) {
lfs->pcache.buffer = lfs->cfg->prog_buffer;
} else {
lfs->pcache.buffer = lfs_malloc(lfs->cfg->prog_size);
if (!lfs->pcache.buffer) {
return LFS_ERR_NOMEM;
}
}
// setup lookahead, round down to nearest 32-bits
LFS_ASSERT(lfs->cfg->lookahead % 32 == 0);
LFS_ASSERT(lfs->cfg->lookahead > 0);
if (lfs->cfg->lookahead_buffer) {
lfs->free.buffer = lfs->cfg->lookahead_buffer;
} else {
lfs->free.buffer = lfs_malloc(lfs->cfg->lookahead/8);
if (!lfs->free.buffer) {
return LFS_ERR_NOMEM;
}
}
// check that program and read sizes are multiples of the block size
LFS_ASSERT(lfs->cfg->prog_size % lfs->cfg->read_size == 0);
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->prog_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);
// check that the size limits are sane
LFS_ASSERT(lfs->cfg->inline_size <= LFS_INLINE_MAX);
LFS_ASSERT(lfs->cfg->inline_size <= lfs->cfg->read_size);
lfs->inline_size = lfs->cfg->inline_size;
if (!lfs->inline_size) {
lfs->inline_size = lfs_min(LFS_INLINE_MAX, lfs->cfg->read_size);
}
LFS_ASSERT(lfs->cfg->attrs_size <= LFS_ATTRS_MAX);
lfs->attrs_size = lfs->cfg->attrs_size;
if (!lfs->attrs_size) {
lfs->attrs_size = LFS_ATTRS_MAX;
}
LFS_ASSERT(lfs->cfg->name_size <= LFS_NAME_MAX);
lfs->name_size = lfs->cfg->name_size;
if (!lfs->name_size) {
lfs->name_size = LFS_NAME_MAX;
}
// setup default state
lfs->root[0] = 0xffffffff;
lfs->root[1] = 0xffffffff;
lfs->files = NULL;
lfs->dirs = NULL;
lfs->deorphaned = false;
return 0;
}
static int lfs_deinit(lfs_t *lfs) {
// free allocated memory
if (!lfs->cfg->read_buffer) {
lfs_free(lfs->rcache.buffer);
}
if (!lfs->cfg->prog_buffer) {
lfs_free(lfs->pcache.buffer);
}
if (!lfs->cfg->lookahead_buffer) {
lfs_free(lfs->free.buffer);
}
return 0;
}
int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
lfs->free.off = 0;
lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
lfs->free.i = 0;
lfs_alloc_ack(lfs);
// create superblock dir
lfs_dir_t superdir;
err = lfs_dir_alloc(lfs, &superdir);
if (err) {
return err;
}
// write root directory
lfs_dir_t root;
err = lfs_dir_alloc(lfs, &root);
if (err) {
return err;
}
err = lfs_dir_commit(lfs, &root, NULL, 0);
if (err) {
return err;
}
lfs->root[0] = root.pair[0];
lfs->root[1] = root.pair[1];
superdir.d.tail[0] = lfs->root[0];
superdir.d.tail[1] = lfs->root[1];
// write one superblock
lfs_superblock_t superblock;
superblock.d.version = LFS_DISK_VERSION,
superblock.d.root[0] = lfs->root[0];
superblock.d.root[1] = lfs->root[1];
superblock.d.block_size = lfs->cfg->block_size;
superblock.d.block_count = lfs->cfg->block_count;
superblock.d.inline_size = lfs->inline_size;
superblock.d.attrs_size = lfs->attrs_size;
superblock.d.name_size = lfs->name_size;
lfs_entry_t superentry;
superentry.d.type = LFS_STRUCT_DIR | LFS_TYPE_SUPERBLOCK;
superentry.d.elen = sizeof(superblock.d);
superentry.d.alen = 0;
superentry.d.nlen = strlen("littlefs");
superentry.off = sizeof(superdir.d);
superentry.size = 0;
lfs_entry_tole32(&superentry.d);
lfs_superblock_tole32(&superblock.d);
err = lfs_dir_set(lfs, &superdir, &superentry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, 0, &superentry.d, 4},
{LFS_FROM_MEM, 0, 0, &superblock.d, sizeof(superblock.d)},
{LFS_FROM_MEM, 0, 0, "littlefs", superentry.d.nlen}}, 3);
if (err) {
return err;
}
// sanity check that fetch works
err = lfs_dir_fetch(lfs, &superdir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
return lfs_deinit(lfs);
}
int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// setup free lookahead
lfs->free.off = 0;
lfs->free.size = 0;
lfs->free.i = 0;
lfs_alloc_ack(lfs);
// load superblock
lfs_dir_t dir;
err = lfs_dir_fetch(lfs, &dir, (const lfs_block_t[2]){0, 1});
if (err) {
if (err == LFS_ERR_CORRUPT) {
LFS_ERROR("Invalid superblock at %d %d", 0, 1);
}
return err;
}
lfs_entry_t entry = {.off = sizeof(dir.d)};
err = lfs_dir_get(lfs, &dir, entry.off, &entry.d, sizeof(entry.d));
if (err) {
return err;
}
lfs_superblock_t superblock;
memset(&superblock.d, 0, sizeof(superblock.d));
err = lfs_dir_get(lfs, &dir,
sizeof(dir.d)+4, &superblock.d,
lfs_min(sizeof(superblock.d), lfs_entry_elen(&entry)));
lfs_superblock_fromle32(&superblock.d);
if (err) {
return err;
}
char magic[8];
err = lfs_dir_get(lfs, &dir,
sizeof(dir.d)+lfs_entry_size(&entry)-entry.d.nlen, magic,
lfs_min(sizeof(magic), entry.d.nlen));
if (err) {
return err;
}
if (memcmp(magic, "littlefs", 8) != 0) {
LFS_ERROR("Invalid superblock at %d %d", 0, 1);
return LFS_ERR_CORRUPT;
}
uint16_t major_version = (0xffff & (superblock.d.version >> 16));
uint16_t minor_version = (0xffff & (superblock.d.version >> 0));
if ((major_version != LFS_DISK_VERSION_MAJOR ||
minor_version > LFS_DISK_VERSION_MINOR)) {
LFS_ERROR("Invalid version %d.%d", major_version, minor_version);
return LFS_ERR_INVAL;
}
if (superblock.d.inline_size) {
if (superblock.d.inline_size > lfs->inline_size) {
LFS_ERROR("Unsupported inline size (%d > %d)",
superblock.d.inline_size, lfs->inline_size);
return LFS_ERR_INVAL;
}
lfs->inline_size = superblock.d.inline_size;
}
if (superblock.d.attrs_size) {
if (superblock.d.attrs_size > lfs->attrs_size) {
LFS_ERROR("Unsupported attrs size (%d > %d)",
superblock.d.attrs_size, lfs->attrs_size);
return LFS_ERR_INVAL;
}
lfs->attrs_size = superblock.d.attrs_size;
}
if (superblock.d.name_size) {
if (superblock.d.name_size > lfs->name_size) {
LFS_ERROR("Unsupported name size (%d > %d)",
superblock.d.name_size, lfs->name_size);
return LFS_ERR_INVAL;
}
lfs->name_size = superblock.d.name_size;
}
lfs->root[0] = superblock.d.root[0];
lfs->root[1] = superblock.d.root[1];
return 0;
}
int lfs_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// Internal filesystem filesystem operations ///
int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
if (lfs_pairisnull(lfs->root)) {
return 0;
}
// iterate over metadata pairs
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;
}
}
lfs_dir_t dir;
int err = lfs_dir_fetch(lfs, &dir, cwd);
if (err) {
return err;
}
// iterate over contents
lfs_entry_t entry;
while (dir.off + sizeof(entry.d) <= (0x7fffffff & dir.d.size)-4) {
err = lfs_dir_get(lfs, &dir,
dir.off, &entry.d, sizeof(entry.d));
lfs_entry_fromle32(&entry.d);
if (err) {
return err;
}
dir.off += lfs_entry_size(&entry);
if ((0x70 & entry.d.type) == LFS_STRUCT_CTZ) {
err = lfs_ctz_traverse(lfs, &lfs->rcache, NULL,
entry.d.u.file.head, entry.d.u.file.size, cb, data);
if (err) {
return err;
}
}
}
cwd[0] = dir.d.tail[0];
cwd[1] = dir.d.tail[1];
if (lfs_pairisnull(cwd)) {
break;
}
}
// iterate over any open files
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if ((f->flags & LFS_F_DIRTY) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &lfs->rcache, &f->cache,
f->head, f->size, cb, data);
if (err) {
return err;
}
}
if ((f->flags & LFS_F_WRITING) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &lfs->rcache, &f->cache,
f->block, f->pos, cb, data);
if (err) {
return err;
}
}
}
return 0;
}
static int lfs_pred(lfs_t *lfs, const lfs_block_t dir[2], lfs_dir_t *pdir) {
if (lfs_pairisnull(lfs->root)) {
return 0;
}
// iterate over all directory directory entries
int err = lfs_dir_fetch(lfs, pdir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
while (!lfs_pairisnull(pdir->d.tail)) {
if (lfs_paircmp(pdir->d.tail, dir) == 0) {
return true;
}
err = lfs_dir_fetch(lfs, pdir, pdir->d.tail);
if (err) {
return err;
}
}
return false;
}
static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_dir_t *parent, lfs_entry_t *entry) {
if (lfs_pairisnull(lfs->root)) {
return 0;
}
parent->d.tail[0] = 0;
parent->d.tail[1] = 1;
// iterate over all directory directory entries
while (!lfs_pairisnull(parent->d.tail)) {
int err = lfs_dir_fetch(lfs, parent, parent->d.tail);
if (err) {
return err;
}
while (true) {
err = lfs_dir_next(lfs, parent, entry);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
if (((0x70 & entry->d.type) == LFS_STRUCT_DIR) &&
lfs_paircmp(entry->d.u.dir, dir) == 0) {
return true;
}
}
}
return false;
}
static int lfs_moved(lfs_t *lfs, const void *e) {
if (lfs_pairisnull(lfs->root)) {
return 0;
}
// skip superblock
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
// iterate over all directory directory entries
lfs_entry_t entry;
while (!lfs_pairisnull(cwd.d.tail)) {
err = lfs_dir_fetch(lfs, &cwd, cwd.d.tail);
if (err) {
return err;
}
while (true) {
err = lfs_dir_next(lfs, &cwd, &entry);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
if (!(LFS_STRUCT_MOVED & entry.d.type) &&
memcmp(&entry.d.u, e, sizeof(entry.d.u)) == 0) {
return true;
}
}
}
return false;
}
static int lfs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], const lfs_block_t newpair[2]) {
// find parent
lfs_dir_t parent;
lfs_entry_t entry;
int res = lfs_parent(lfs, oldpair, &parent, &entry);
if (res < 0) {
return res;
}
if (res) {
// update disk, this creates a desync
entry.d.u.dir[0] = newpair[0];
entry.d.u.dir[1] = newpair[1];
int err = lfs_dir_set(lfs, &parent, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, sizeof(entry.d),
&entry.d, sizeof(entry.d)}}, 1);
if (err) {
return err;
}
// update internal root
if (lfs_paircmp(oldpair, lfs->root) == 0) {
LFS_DEBUG("Relocating root %d %d", newpair[0], newpair[1]);
lfs->root[0] = newpair[0];
lfs->root[1] = newpair[1];
}
// clean up bad block, which should now be a desync
return lfs_deorphan(lfs);
}
// find pred
res = lfs_pred(lfs, oldpair, &parent);
if (res < 0) {
return res;
}
if (res) {
// just replace bad pair, no desync can occur
parent.d.tail[0] = newpair[0];
parent.d.tail[1] = newpair[1];
return lfs_dir_commit(lfs, &parent, NULL, 0);
}
// couldn't find dir, must be new
return 0;
}
int lfs_deorphan(lfs_t *lfs) {
lfs->deorphaned = true;
if (lfs_pairisnull(lfs->root)) {
return 0;
}
lfs_dir_t pdir = {.d.size = 0x80000000};
lfs_dir_t cwd = {.d.tail[0] = 0, .d.tail[1] = 1};
// iterate over all directory directory entries
while (!lfs_pairisnull(cwd.d.tail)) {
int err = lfs_dir_fetch(lfs, &cwd, cwd.d.tail);
if (err) {
return err;
}
// check head blocks for orphans
if (!(0x80000000 & pdir.d.size)) {
// check if we have a parent
lfs_dir_t parent;
lfs_entry_t entry;
int res = lfs_parent(lfs, pdir.d.tail, &parent, &entry);
if (res < 0) {
return res;
}
if (!res) {
// we are an orphan
LFS_DEBUG("Found orphan %d %d",
pdir.d.tail[0], pdir.d.tail[1]);
pdir.d.tail[0] = cwd.d.tail[0];
pdir.d.tail[1] = cwd.d.tail[1];
err = lfs_dir_commit(lfs, &pdir, NULL, 0);
if (err) {
return err;
}
break;
}
if (!lfs_pairsync(entry.d.u.dir, pdir.d.tail)) {
// we have desynced
LFS_DEBUG("Found desync %d %d",
entry.d.u.dir[0], entry.d.u.dir[1]);
pdir.d.tail[0] = entry.d.u.dir[0];
pdir.d.tail[1] = entry.d.u.dir[1];
err = lfs_dir_commit(lfs, &pdir, NULL, 0);
if (err) {
return err;
}
break;
}
}
// check entries for moves
lfs_entry_t entry;
while (true) {
err = lfs_dir_next(lfs, &cwd, &entry);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
// found moved entry
if (entry.d.type & LFS_STRUCT_MOVED) {
int moved = lfs_moved(lfs, &entry.d.u);
if (moved < 0) {
return moved;
}
if (moved) {
LFS_DEBUG("Found move %d %d",
entry.d.u.dir[0], entry.d.u.dir[1]);
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, entry.size, NULL, 0}}, 1);
if (err) {
return err;
}
} else {
LFS_DEBUG("Found partial move %d %d",
entry.d.u.dir[0], entry.d.u.dir[1]);
entry.d.type &= ~LFS_STRUCT_MOVED;
err = lfs_dir_set(lfs, &cwd, &entry, (struct lfs_region[]){
{LFS_FROM_MEM, 0, sizeof(entry.d),
&entry.d, sizeof(entry.d)}}, 1);
if (err) {
return err;
}
}
}
}
memcpy(&pdir, &cwd, sizeof(pdir));
}
return 0;
}
/// External filesystem filesystem operations ///
int lfs_fs_getattrs(lfs_t *lfs, const struct lfs_attr *attrs, int count) {
lfs_dir_t dir;
int err = lfs_dir_fetch(lfs, &dir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
lfs_entry_t entry = {.off = sizeof(dir.d)};
err = lfs_dir_get(lfs, &dir, entry.off, &entry.d, sizeof(entry.d));
if (err) {
return err;
}
entry.size = lfs_entry_size(&entry);
return lfs_dir_getattrs(lfs, &dir, &entry, attrs, count);
}
int lfs_fs_setattrs(lfs_t *lfs, const struct lfs_attr *attrs, int count) {
lfs_dir_t dir;
int err = lfs_dir_fetch(lfs, &dir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
lfs_entry_t entry = {.off = sizeof(dir.d)};
err = lfs_dir_get(lfs, &dir, entry.off, &entry.d, sizeof(entry.d));
if (err) {
return err;
}
entry.size = lfs_entry_size(&entry);
return lfs_dir_setattrs(lfs, &dir, &entry, attrs, count);
}
static int lfs_fs_size_count(void *p, lfs_block_t block) {
lfs_size_t *size = p;
*size += 1;
return 0;
}
lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
lfs_size_t size = 0;
int err = lfs_traverse(lfs, lfs_fs_size_count, &size);
if (err) {
return err;
}
return size;
}
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