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aeca7667b3
third_party_littlefs/lfs.c
Christopher Haster aeca7667b3 Switched to strongly ordered directories 
Instead of storing files in an arbitrary order, we now store files in
ascending lexicographical order by filename.

Although a big change, this actually has little impact on how littlefs
works internally. We need to support file insertion, and compare file
names to find our position. But since we already need to scan the entire
directory block, this adds relatively little overhead.

What this does allow, is the potential to add B-tree support in the
future in a backwards compatible manner.

How could you add B-trees to littlefs?
1. Add an optional "child" tag with a pointer that allows you to skip to
   a position in the metadata-pair list that composes the directory
2. When splitting a metadata-pair (sound familiar?), we either insert a
   second child tag in our parent, or we create a new root containing
   the child tags.
3. Each layer needs a bit stored in the tail-pointer to indicate if
   we're going to the next layer. This can be created trivially when we
   create a new root.
4. During lookup we keep two pointers containing the bounds of our
   search. We may need to iterate through multiple metadata-pairs in our
   linked-list, but this gives us a O(log n) lookup cost in a balanced
   tree.
5. During deletion we also delete any children pointers. Note that
   children pointers must come before the actual file entry.

This gives us a B-tree implementation that is compatible with the
current directory layout (assuming the files are ordered). This means
that B-trees could be supported by a host PC and ignored on a small
device. And during power-loss, we never end up with a broken filesystem,
just a less-than-optimal tree.

Note that we don't handle removes, so it's possible for a tree to become
unbalanced. But worst case that's the same as the current linked-list
implementation.

All we need to do now is keep directories ordered. If we decide to drop
B-tree support in the future or the B-tree implementation turns out
inherently flawed, we can just drop the ordered requirement without
breaking compatibility and recover the code cost.
2018-10-18 10:00:49 -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 inline void lfs_cache_drop(lfs_t *lfs, lfs_cache_t *rcache) {
// do not zero, cheaper if cache is readonly or only going to be
// written with identical data (during relocates)
(void)lfs;
rcache->block = 0xffffffff;
}
static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
// zero to avoid information leak
memset(pcache->buffer, 0xff, lfs->cfg->prog_size);
pcache->block = 0xffffffff;
}
static int lfs_bd_read(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff);
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT;
}
while (size > 0) {
lfs_size_t diff = size;
if (pcache && block == pcache->block &&
off < pcache->off + pcache->size) {
if (off >= pcache->off) {
// is already in pcache?
diff = lfs_min(diff, pcache->size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// pcache takes priority
diff = lfs_min(diff, pcache->off-off);
}
if (block == rcache->block &&
off < rcache->off + rcache->size) {
if (off >= rcache->off) {
// is already in rcache?
diff = lfs_min(diff, rcache->size - (off-rcache->off));
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// rcache takes priority
diff = lfs_min(diff, rcache->off-off);
}
if (size >= hint && off % lfs->cfg->read_size == 0 &&
size >= lfs->cfg->read_size) {
// bypass cache?
diff = lfs_aligndown(diff, lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
data += diff;
off += diff;
size -= diff;
continue;
}
// load to cache, first condition can no longer fail
LFS_ASSERT(block < lfs->cfg->block_count);
rcache->block = block;
rcache->off = lfs_aligndown(off, lfs->cfg->read_size);
rcache->size = lfs_min(lfs_alignup(off+hint, lfs->cfg->read_size),
lfs_min(lfs->cfg->block_size - rcache->off,
lfs->cfg->cache_size));
int err = lfs->cfg->read(lfs->cfg, rcache->block,
rcache->off, rcache->buffer, rcache->size);
if (err) {
return err;
}
}
return 0;
}
static int lfs_bd_cmp(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
for (lfs_off_t i = 0; i < size; i++) {
uint8_t dat;
int err = lfs_bd_read(lfs,
pcache, rcache, hint-i,
block, off+i, &dat, 1);
if (err) {
return err;
}
if (dat != data[i]) {
return (dat < data[i]) ? 1 : 2;
}
}
return 0;
}
static int lfs_bd_flush(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
if (pcache->block != 0xffffffff && pcache->block != 0xfffffffe) {
LFS_ASSERT(pcache->block < lfs->cfg->block_count);
lfs_size_t diff = lfs_alignup(pcache->size, lfs->cfg->prog_size);
int err = lfs->cfg->prog(lfs->cfg, pcache->block,
pcache->off, pcache->buffer, diff);
if (err) {
return err;
}
if (validate) {
// check data on disk
lfs_cache_drop(lfs, rcache);
int res = lfs_bd_cmp(lfs,
NULL, rcache, diff,
pcache->block, pcache->off, pcache->buffer, diff);
if (res) {
return (res < 0) ? res : LFS_ERR_CORRUPT;
}
}
lfs_cache_zero(lfs, pcache);
}
return 0;
}
static int lfs_bd_sync(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
lfs_cache_drop(lfs, rcache);
int err = lfs_bd_flush(lfs, pcache, rcache, validate);
if (err) {
return err;
}
return lfs->cfg->sync(lfs->cfg);
}
static int lfs_bd_prog(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate,
lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff);
LFS_ASSERT(off + size <= lfs->cfg->block_size);
while (size > 0) {
if (block == pcache->block &&
off >= pcache->off &&
off < pcache->off + lfs->cfg->cache_size) {
// already fits in pcache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->cache_size - (off-pcache->off));
memcpy(&pcache->buffer[off-pcache->off], data, diff);
data += diff;
off += diff;
size -= diff;
pcache->size = off - pcache->off;
if (pcache->size == lfs->cfg->cache_size) {
// eagerly flush out pcache if we fill up
int err = lfs_bd_flush(lfs, pcache, rcache, validate);
if (err) {
return err;
}
}
continue;
}
// pcache must have been flushed, either by programming and
// entire block or manually flushing the pcache
LFS_ASSERT(pcache->block == 0xffffffff);
// prepare pcache, first condition can no longer fail
pcache->block = block;
pcache->off = lfs_aligndown(off, lfs->cfg->prog_size);
pcache->size = 0;
}
return 0;
}
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);
}
/// Small type-level utilities ///
// operations on block pairs
static inline void lfs_pair_swap(lfs_block_t pair[2]) {
lfs_block_t t = pair[0];
pair[0] = pair[1];
pair[1] = t;
}
static inline bool lfs_pair_isnull(const lfs_block_t pair[2]) {
return pair[0] == 0xffffffff || pair[1] == 0xffffffff;
}
static inline int lfs_pair_cmp(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return !(paira[0] == pairb[0] || paira[1] == pairb[1] ||
paira[0] == pairb[1] || paira[1] == pairb[0]);
}
static inline bool lfs_pair_sync(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return (paira[0] == pairb[0] && paira[1] == pairb[1]) ||
(paira[0] == pairb[1] && paira[1] == pairb[0]);
}
static inline void lfs_pair_fromle32(lfs_block_t pair[2]) {
pair[0] = lfs_fromle32(pair[0]);
pair[1] = lfs_fromle32(pair[1]);
}
static inline void lfs_pair_tole32(lfs_block_t pair[2]) {
pair[0] = lfs_tole32(pair[0]);
pair[1] = lfs_tole32(pair[1]);
}
// operations on 32-bit entry tags
typedef uint32_t lfs_tag_t;
typedef int32_t lfs_stag_t;
#define LFS_MKTAG(type, id, size) \
(((lfs_tag_t)(type) << 22) | ((lfs_tag_t)(id) << 13) | (lfs_tag_t)(size))
static inline bool lfs_tag_isvalid(lfs_tag_t tag) {
return !(tag & 0x80000000);
}
static inline bool lfs_tag_isuser(lfs_tag_t tag) {
return (tag & 0x40000000);
}
static inline bool lfs_tag_isdelete(lfs_tag_t tag) {
return ((int32_t)(tag << 19) >> 19) == -1;
}
static inline uint16_t lfs_tag_type(lfs_tag_t tag) {
return (tag & 0x7fc00000) >> 22;
}
static inline uint16_t lfs_tag_subtype(lfs_tag_t tag) {
return ((tag & 0x7c000000) >> 26) << 4;
}
static inline uint16_t lfs_tag_id(lfs_tag_t tag) {
return (tag & 0x003fe000) >> 13;
}
static inline lfs_size_t lfs_tag_size(lfs_tag_t tag) {
return tag & 0x00001fff;
}
static inline lfs_size_t lfs_tag_dsize(lfs_tag_t tag) {
return sizeof(tag) + lfs_tag_size(tag + lfs_tag_isdelete(tag));
}
// operations on attributes in attribute lists
struct lfs_mattr {
lfs_tag_t tag;
const void *buffer;
const struct lfs_mattr *next;
};
#define LFS_MKATTR(type, id, buffer, size, next) \
&(const struct lfs_mattr){LFS_MKTAG(type, id, size), (buffer), (next)}
struct lfs_diskoff {
lfs_block_t block;
lfs_off_t off;
};
// operations on set of globals
static inline void lfs_global_xor(struct lfs_globals *a,
const struct lfs_globals *b) {
uint32_t *a32 = (uint32_t *)a;
const uint32_t *b32 = (const uint32_t *)b;
for (int i = 0; i < sizeof(struct lfs_globals)/4; i++) {
a32[i] ^= b32[i];
}
}
static inline bool lfs_global_iszero(const struct lfs_globals *a) {
const uint32_t *a32 = (const uint32_t *)a;
for (int i = 0; i < sizeof(struct lfs_globals)/4; i++) {
if (a32[i] != 0) {
return false;
}
}
return true;
}
static inline void lfs_global_zero(struct lfs_globals *a) {
lfs_global_xor(a, a);
}
static inline void lfs_global_fromle32(struct lfs_globals *a) {
lfs_pair_fromle32(a->pair);
a->id = lfs_fromle16(a->id);
}
static inline void lfs_global_tole32(struct lfs_globals *a) {
lfs_pair_tole32(a->pair);
a->id = lfs_tole16(a->id);
}
static inline void lfs_global_move(lfs_t *lfs,
bool hasmove, const lfs_block_t pair[2], uint16_t id) {
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->locals, &lfs->globals);
lfs->globals.hasmove = hasmove;
lfs->globals.pair[0] = pair[0];
lfs->globals.pair[1] = pair[1];
lfs->globals.id = id;
lfs_global_xor(&lfs->locals, &lfs->globals);
lfs_global_tole32(&lfs->locals);
}
static inline void lfs_global_orphans(lfs_t *lfs, int8_t orphans) {
lfs->locals.orphans ^= (lfs->globals.orphans == 0);
lfs->globals.orphans += orphans;
lfs->locals.orphans ^= (lfs->globals.orphans == 0);
}
// other endianness operations
static void lfs_ctz_fromle32(struct lfs_ctz *ctz) {
ctz->head = lfs_fromle32(ctz->head);
ctz->size = lfs_fromle32(ctz->size);
}
static void lfs_ctz_tole32(struct lfs_ctz *ctz) {
ctz->head = lfs_tole32(ctz->head);
ctz->size = lfs_tole32(ctz->size);
}
static inline void lfs_superblock_fromle32(lfs_superblock_t *superblock) {
superblock->version = lfs_fromle32(superblock->version);
superblock->block_size = lfs_fromle32(superblock->block_size);
superblock->block_count = lfs_fromle32(superblock->block_count);
superblock->name_max = lfs_fromle32(superblock->name_max);
superblock->inline_max = lfs_fromle32(superblock->inline_max);
superblock->attr_max = lfs_fromle32(superblock->attr_max);
}
static inline void lfs_superblock_tole32(lfs_superblock_t *superblock) {
superblock->version = lfs_tole32(superblock->version);
superblock->block_size = lfs_tole32(superblock->block_size);
superblock->block_count = lfs_tole32(superblock->block_count);
superblock->name_max = lfs_tole32(superblock->name_max);
superblock->inline_max = lfs_tole32(superblock->inline_max);
superblock->attr_max = lfs_tole32(superblock->attr_max);
}
/// Internal operations predeclared here ///
static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs);
static int lfs_fs_pred(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *pdir);
static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *parent);
static int lfs_fs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], lfs_block_t newpair[2]);
static int lfs_fs_forceconsistency(lfs_t *lfs);
static int lfs_deinit(lfs_t *lfs);
/// Block allocator ///
static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
lfs_t *lfs = (lfs_t*)p;
lfs_block_t off = ((block - lfs->free.off)
+ lfs->cfg->block_count) % lfs->cfg->block_count;
if (off < lfs->free.size) {
lfs->free.buffer[off / 32] |= 1U << (off % 32);
}
return 0;
}
static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
while (true) {
while (lfs->free.i != lfs->free.size) {
lfs_block_t off = lfs->free.i;
lfs->free.i += 1;
lfs->free.ack -= 1;
if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
// found a free block
*block = (lfs->free.off + off) % lfs->cfg->block_count;
// eagerly find next off so an alloc ack can
// discredit old lookahead blocks
while (lfs->free.i != lfs->free.size &&
(lfs->free.buffer[lfs->free.i / 32]
& (1U << (lfs->free.i % 32)))) {
lfs->free.i += 1;
lfs->free.ack -= 1;
}
return 0;
}
}
// check if we have looked at all blocks since last ack
if (lfs->free.ack == 0) {
LFS_WARN("No more free space %"PRIu32,
lfs->free.i + lfs->free.off);
return LFS_ERR_NOSPC;
}
lfs->free.off = (lfs->free.off + lfs->free.size)
% lfs->cfg->block_count;
lfs->free.size = lfs_min(8*lfs->cfg->lookahead_size, lfs->free.ack);
lfs->free.i = 0;
// find mask of free blocks from tree
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_size);
int err = lfs_fs_traverse(lfs, lfs_alloc_lookahead, lfs);
if (err) {
return err;
}
}
}
static void lfs_alloc_ack(lfs_t *lfs) {
lfs->free.ack = lfs->cfg->block_count;
}
/// Metadata pair and directory operations ///
static int lfs_dir_traverse(lfs_t *lfs,
const lfs_mdir_t *dir, const struct lfs_mattr *attrs,
lfs_tag_t matchmask, lfs_tag_t matchtag, lfs_stag_t matchdiff,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
lfs_block_t block = dir->pair[0];
lfs_off_t off = dir->off;
lfs_tag_t ntag = dir->etag;
bool lastcommit = false;
matchtag += matchdiff;
// iterate over dir block backwards (for faster lookups)
while (attrs || off >= sizeof(lfs_tag_t) + lfs_tag_dsize(ntag)) {
lfs_tag_t tag;
const void *buffer;
struct lfs_diskoff disk;
if (attrs) {
tag = attrs->tag;
buffer = attrs->buffer;
attrs = attrs->next;
} else {
off -= lfs_tag_dsize(ntag);
tag = ntag;
buffer = &disk;
disk.block = block;
disk.off = off + sizeof(tag);
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, sizeof(ntag),
block, off, &ntag, sizeof(ntag));
if (err) {
return err;
}
ntag = lfs_fromle32(ntag) ^ tag;
tag |= 0x80000000;
}
if (lfs_tag_subtype(tag) == LFS_TYPE_CRC) {
lastcommit = 2 & lfs_tag_type(tag);
} else if (lfs_tag_subtype(tag) == LFS_TYPE_DELETE) {
// something was deleted, need to move around it
if (lfs_tag_id(tag) <= lfs_tag_id(matchtag - matchdiff)) {
matchdiff -= LFS_MKTAG(0, 1, 0);
}
}
if ((tag & matchmask) == ((matchtag - matchdiff) & matchmask) &&
!(lfs_tag_isdelete(tag) && lastcommit)) {
int res = cb(data, tag + matchdiff, buffer);
if (res) {
return res;
}
}
if (lfs_tag_subtype(tag) == LFS_TYPE_NAME) {
// found where something was created
if (lfs_tag_id(tag) == lfs_tag_id(matchtag - matchdiff)) {
break;
} else if (lfs_tag_id(tag) < lfs_tag_id(matchtag - matchdiff)) {
matchdiff += LFS_MKTAG(0, 1, 0);
}
}
}
return 0;
}
static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2],
lfs_tag_t matchmask, lfs_tag_t matchtag,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
// find the block with the most recent revision
uint32_t revs[2];
int r = 0;
for (int i = 0; i < 2; i++) {
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, sizeof(revs[i]),
pair[i], 0, &revs[i], sizeof(revs[i]));
revs[i] = lfs_fromle32(revs[i]);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (lfs_scmp(revs[i], revs[(i+1)%2]) > 0 || err == LFS_ERR_CORRUPT) {
r = i;
}
}
// now fetch the actual dir (and find match)
lfs_stag_t foundtag = 0;
dir->pair[0] = pair[0];
dir->pair[1] = pair[1];
dir->off = 0;
if (r != 0) {
lfs_pair_swap(dir->pair);
lfs_pair_swap(revs);
}
// scan tags and check crcs
for (int i = 0; i < 2; i++) {
lfs_block_t block = dir->pair[0];
lfs_off_t off = sizeof(uint32_t);
lfs_tag_t ptag = 0xffffffff;
lfs_tag_t tempfoundtag = foundtag;
lfs_mdir_t temp = {
.pair = {dir->pair[0], dir->pair[1]},
.rev = revs[0],
.tail = {0xffffffff, 0xffffffff},
.split = false,
.count = 0,
};
temp.rev = lfs_tole32(temp.rev);
uint32_t crc = lfs_crc(0xffffffff, &temp.rev, sizeof(temp.rev));
temp.rev = lfs_fromle32(temp.rev);
while (true) {
// extract next tag
lfs_tag_t tag;
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
block, off, &tag, sizeof(tag));
if (err) {
if (err == LFS_ERR_CORRUPT) {
// can't continue?
dir->erased = false;
break;
}
return err;
}
crc = lfs_crc(crc, &tag, sizeof(tag));
tag = lfs_fromle32(tag) ^ ptag;
// next commit not yet programmed
if (!lfs_tag_isvalid(tag)) {
dir->erased = (lfs_tag_subtype(ptag) == LFS_TYPE_CRC);
break;
}
// check we're in valid range
if (off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
dir->erased = false;
break;
}
if (lfs_tag_subtype(tag) == LFS_TYPE_CRC) {
// check the crc attr
uint32_t dcrc;
err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
block, off+sizeof(tag), &dcrc, sizeof(dcrc));
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return err;
}
dcrc = lfs_fromle32(dcrc);
if (crc != dcrc) {
dir->erased = false;
break;
}
// reset the next bit if we need to
tag ^= (lfs_tag_type(tag) & 1) << 31;
lfs->seed ^= crc;
crc = 0xffffffff;
// update with what's found so far
foundtag = tempfoundtag;
*dir = temp;
dir->off = off + lfs_tag_dsize(tag);
dir->etag = tag;
} else {
// crc the entry first, leaving it in the cache
for (lfs_off_t j = sizeof(tag); j < lfs_tag_dsize(tag); j++) {
uint8_t dat;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
block, off+j, &dat, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return err;
}
crc = lfs_crc(crc, &dat, 1);
}
// check for special tags
if (lfs_tag_subtype(tag) == LFS_TYPE_NAME) {
temp.count += 1;
if (tempfoundtag &&
lfs_tag_id(tag) <= lfs_tag_id(tempfoundtag)) {
tempfoundtag += LFS_MKTAG(0, 1, 0);
}
} else if (lfs_tag_subtype(tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(temp.count > 0);
temp.count -= 1;
if (tempfoundtag &&
lfs_tag_id(tag) == lfs_tag_id(tempfoundtag)) {
tempfoundtag = 0;
} else if (tempfoundtag &&
lfs_tag_id(tag) < lfs_tag_id(tempfoundtag)) {
tempfoundtag -= LFS_MKTAG(0, 1, 0);
}
} else if (lfs_tag_subtype(tag) == LFS_TYPE_TAIL) {
temp.split = (lfs_tag_type(tag) & 1);
err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
block, off+sizeof(tag),
&temp.tail, sizeof(temp.tail));
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
}
lfs_pair_fromle32(temp.tail);
}
if ((tag & matchmask) == (matchtag & matchmask)) {
// found a match?
if (lfs_tag_isdelete(tag)) {
tempfoundtag = 0;
} else if (cb) {
int res = cb(data, tag, &(struct lfs_diskoff){
block, off+sizeof(tag)});
if (res < 0) {
if (res == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return res;
}
if (res && (!tempfoundtag ||
lfs_tag_id(res) <= lfs_tag_id(tempfoundtag))) {
tempfoundtag = res;
}
}
}
}
ptag = tag;
off += lfs_tag_dsize(tag);
}
// consider what we have good enough
if (dir->off > 0) {
// synthetic move
if (foundtag &&
lfs->globals.hasmove &&
lfs_pair_cmp(dir->pair, lfs->globals.pair) == 0) {
if (lfs->globals.id == lfs_tag_id(foundtag)) {
foundtag = 0;
} else if (lfs->globals.id < lfs_tag_id(foundtag)) {
foundtag -= LFS_MKTAG(0, 1, 0);
}
}
return foundtag;
}
// failed, try the other crc?
lfs_pair_swap(dir->pair);
lfs_pair_swap(revs);
}
LFS_ERROR("Corrupted dir pair at %"PRIu32" %"PRIu32,
dir->pair[0], dir->pair[1]);
return LFS_ERR_CORRUPT;
}
static int lfs_dir_fetch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2]) {
return lfs_dir_fetchmatch(lfs, dir, pair,
0xffffffff, 0x00000000, NULL, NULL);
}
struct lfs_dir_get_match {
lfs_t *lfs;
void *buffer;
lfs_size_t size;
bool compacting;
};
static int lfs_dir_get_match(void *data,
lfs_tag_t tag, const void *buffer) {
struct lfs_dir_get_match *get = data;
lfs_t *lfs = get->lfs;
const struct lfs_diskoff *disk = buffer;
if (lfs_tag_isdelete(tag) && !get->compacting) {
return LFS_ERR_NOENT;
}
if (get->buffer) {
lfs_size_t diff = lfs_min(lfs_tag_size(tag), get->size);
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, diff,
disk->block, disk->off, get->buffer, diff);
if (err) {
return err;
}
memset((uint8_t*)get->buffer + diff, 0, get->size - diff);
}
return tag & 0x7fffffff;
}
static lfs_stag_t lfs_dir_get(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_tag_t getmask, lfs_tag_t gettag, void *buffer) {
lfs_stag_t getdiff = 0;
if (lfs->globals.hasmove &&
lfs_pair_cmp(dir->pair, lfs->globals.pair) == 0 &&
lfs_tag_id(gettag) <= lfs->globals.id) {
// synthetic moves
gettag += LFS_MKTAG(0, 1, 0);
getdiff -= LFS_MKTAG(0, 1, 0);
}
lfs_stag_t res = lfs_dir_traverse(lfs, dir, NULL,
getmask, gettag, getdiff,
lfs_dir_get_match, &(struct lfs_dir_get_match){
lfs, buffer, lfs_tag_size(gettag)});
if (res < 0) {
return res;
}
return res ? res : LFS_ERR_NOENT;
}
static int lfs_dir_getglobals(lfs_t *lfs, const lfs_mdir_t *dir,
struct lfs_globals *globals) {
struct lfs_globals locals;
lfs_stag_t res = lfs_dir_get(lfs, dir, 0x7c000000,
LFS_MKTAG(LFS_TYPE_GLOBALS, 0, 10), &locals);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
if (res != LFS_ERR_NOENT) {
locals.hasmove = (lfs_tag_type(res) & 2);
locals.orphans = (lfs_tag_type(res) & 1);
// xor together to find resulting globals
lfs_global_xor(globals, &locals);
}
return 0;
}
static int lfs_dir_getinfo(lfs_t *lfs, lfs_mdir_t *dir,
uint16_t id, struct lfs_info *info) {
if (id == 0x1ff) {
// special case for root
strcpy(info->name, "/");
info->type = LFS_TYPE_DIR;
return 0;
}
lfs_stag_t tag = lfs_dir_get(lfs, dir, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_NAME, id, lfs->name_max+1), info->name);
if (tag < 0) {
return tag;
}
info->type = lfs_tag_type(tag);
struct lfs_ctz ctz;
tag = lfs_dir_get(lfs, dir, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, id, sizeof(ctz)), &ctz);
if (tag < 0) {
return tag;
}
lfs_ctz_fromle32(&ctz);
if (lfs_tag_type(tag) == LFS_TYPE_CTZSTRUCT) {
info->size = ctz.size;
} else if (lfs_tag_type(tag) == LFS_TYPE_INLINESTRUCT) {
info->size = lfs_tag_size(tag);
}
return 0;
}
struct lfs_dir_find_match {
lfs_t *lfs;
const void *name;
lfs_size_t size;
};
static int lfs_dir_find_match(void *data,
lfs_tag_t tag, const void *buffer) {
struct lfs_dir_find_match *name = data;
lfs_t *lfs = name->lfs;
const struct lfs_diskoff *disk = buffer;
lfs_size_t diff = lfs_min(name->size, lfs_tag_size(tag));
int res = lfs_bd_cmp(lfs,
NULL, &lfs->rcache, diff,
disk->block, disk->off, name->name, diff);
if (res < 0) {
return res;
}
// found match?
if (res == 0 && (name->size == lfs_tag_size(tag) ||
lfs_tag_type(tag) == LFS_TYPE_SUPERBLOCK)) {
return tag;
}
// a greater name found, exit early
if (res == 2 && lfs_tag_type(tag) != LFS_TYPE_SUPERBLOCK) {
return tag | 0x1fff;
}
// no match keep looking
return 0;
}
static int lfs_dir_find(lfs_t *lfs, lfs_mdir_t *dir,
const char **path, uint16_t *id) {
// we reduce path to a single name if we can find it
const char *name = *path;
// default to root dir
lfs_stag_t tag = LFS_MKTAG(LFS_TYPE_DIR, 0x1ff, 0);
dir->tail[0] = lfs->root[0];
dir->tail[1] = lfs->root[1];
while (true) {
nextname:
// skip slashes
name += strspn(name, "/");
lfs_size_t namelen = strcspn(name, "/");
// skip '.' and root '..'
if ((namelen == 1 && memcmp(name, ".", 1) == 0) ||
(namelen == 2 && memcmp(name, "..", 2) == 0)) {
name += namelen;
goto nextname;
}
// skip if matched by '..' in name
const char *suffix = name + namelen;
lfs_size_t sufflen;
int depth = 1;
while (true) {
suffix += strspn(suffix, "/");
sufflen = strcspn(suffix, "/");
if (sufflen == 0) {
break;
}
if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
name = suffix + sufflen;
goto nextname;
}
} else {
depth += 1;
}
suffix += sufflen;
}
// found path
if (name[0] == '\0') {
return tag;
}
// update what we've found so far
*path = name;
// only continue if we hit a directory
if (lfs_tag_type(tag) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
// grab the entry data
if (lfs_tag_id(tag) != 0x1ff) {
lfs_stag_t res = lfs_dir_get(lfs, dir, 0x7c3fe000,
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,
0x7c000000, LFS_MKTAG(LFS_TYPE_NAME, 0, namelen),
lfs_dir_find_match, &(struct lfs_dir_find_match){
lfs, name, namelen});
if (tag < 0) {
return tag;
}
if (id) {
if (strchr(name, '/') != NULL) {
// if path is not only name we're not valid candidate
// for creation
*id = 0x1ff;
} else if (tag) {
*id = lfs_tag_id(tag);
} else {
*id = dir->count;
}
}
if (tag && !lfs_tag_isdelete(tag)) {
break;
}
if (lfs_tag_isdelete(tag) || !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;
lfs_off_t ack;
};
static int lfs_commit_prog(lfs_t *lfs, struct lfs_commit *commit,
const void *buffer, lfs_size_t size) {
lfs_off_t skip = lfs_min(lfs_max(commit->ack, commit->off)
- commit->off, size);
int err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, false,
commit->block, commit->off + skip,
(const uint8_t*)buffer + skip, size - skip);
if (err) {
return err;
}
commit->crc = lfs_crc(commit->crc, buffer, size);
commit->off += size;
commit->ack = lfs_max(commit->off, commit->ack);
return 0;
}
static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
lfs_tag_t tag, const void *buffer);
struct lfs_commit_move_match {
lfs_t *lfs;
struct lfs_commit *commit;
int pass;
};
static int lfs_commit_move_match(void *data,
lfs_tag_t tag, const void *buffer) {
struct lfs_commit_move_match *move = data;
lfs_t *lfs = move->lfs;
struct lfs_commit *commit = move->commit;
if (move->pass == 0) {
if (lfs_tag_subtype(tag) != LFS_TYPE_NAME) {
return 0;
}
} else {
// check if type has already been committed
lfs_stag_t res = lfs_dir_traverse(lfs, &(const lfs_mdir_t){
.pair[0] = commit->block,
.off = commit->off,
.etag = commit->ptag}, NULL,
lfs_tag_isuser(tag) ? 0x7fffe000 : 0x7c3fe000, tag, 0,
lfs_dir_get_match, &(struct lfs_dir_get_match){
lfs, NULL, 0, true});
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
if (res > 0) {
return 0;
}
}
// update id and commit, as we are currently unique
return lfs_commit_attr(lfs, commit, tag, buffer);
}
static int lfs_commit_move(lfs_t *lfs, struct lfs_commit *commit, int pass,
lfs_tag_t frommask, lfs_tag_t fromtag, lfs_stag_t fromdiff,
const lfs_mdir_t *dir, const struct lfs_mattr *attrs) {
return lfs_dir_traverse(lfs, dir, attrs,
frommask, fromtag, fromdiff,
lfs_commit_move_match, &(struct lfs_commit_move_match){
lfs, commit, pass});
}
static int lfs_commit_userattrs(lfs_t *lfs, struct lfs_commit *commit,
uint16_t id, const struct lfs_attr *attrs) {
for (const struct lfs_attr *a = attrs; a; a = a->next) {
int err = lfs_commit_attr(lfs, commit,
LFS_MKTAG(0x100 | a->type, id, a->size), a->buffer);
if (err) {
return err;
}
}
return 0;
}
static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
lfs_tag_t tag, const void *buffer) {
if (lfs_tag_type(tag) == LFS_FROM_MOVE) {
// special case for moves
return lfs_commit_move(lfs, commit, 1,
0x003fe000, LFS_MKTAG(0, lfs_tag_size(tag), 0),
LFS_MKTAG(0, lfs_tag_id(tag), 0) -
LFS_MKTAG(0, lfs_tag_size(tag), 0),
buffer, NULL);
} else if (lfs_tag_type(tag) == LFS_FROM_USERATTRS) {
// special case for custom attributes
return lfs_commit_userattrs(lfs, commit,
lfs_tag_id(tag), 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_tole32((tag & 0x7fffffff) ^ commit->ptag);
int err = lfs_commit_prog(lfs, commit, &ntag, sizeof(ntag));
if (err) {
return err;
}
if (!(tag & 0x80000000)) {
// from memory
err = lfs_commit_prog(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,
&lfs->pcache, &lfs->rcache, dsize-sizeof(tag)-i,
disk->block, disk->off+i, &dat, 1);
if (err) {
return err;
}
err = lfs_commit_prog(lfs, commit, &dat, 1);
if (err) {
return err;
}
}
}
commit->ptag = tag & 0x7fffffff;
return 0;
}
static int lfs_commit_globals(lfs_t *lfs, struct lfs_commit *commit,
struct lfs_globals *globals) {
return lfs_commit_attr(lfs, commit,
LFS_MKTAG(LFS_TYPE_GLOBALS + 2*globals->hasmove + globals->orphans,
0x1ff, 10), globals);
}
static int lfs_commit_crc(lfs_t *lfs, struct lfs_commit *commit,
bool compacting) {
// align to program units
lfs_off_t off = lfs_alignup(commit->off + 2*sizeof(uint32_t),
lfs->cfg->prog_size);
// read erased state from next program unit
lfs_tag_t tag;
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, sizeof(tag),
commit->block, off, &tag, sizeof(tag));
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// build crc tag
bool reset = ~lfs_fromle32(tag) >> 31;
tag = LFS_MKTAG(LFS_TYPE_CRC + 2*compacting + reset,
0x1ff, off - (commit->off+sizeof(lfs_tag_t)));
// write out crc
uint32_t footer[2];
footer[0] = lfs_tole32(tag ^ commit->ptag);
commit->crc = lfs_crc(commit->crc, &footer[0], sizeof(footer[0]));
footer[1] = lfs_tole32(commit->crc);
err = lfs_bd_prog(lfs,
&lfs->pcache, &lfs->rcache, false,
commit->block, commit->off, &footer, sizeof(footer));
if (err) {
return err;
}
commit->off += sizeof(tag)+lfs_tag_size(tag);
commit->ptag = tag ^ (reset << 31);
// flush buffers
err = lfs_bd_sync(lfs, &lfs->pcache, &lfs->rcache, false);
if (err) {
return err;
}
// successful commit, check checksum to make sure
uint32_t crc = 0xffffffff;
lfs_size_t size = commit->off - lfs_tag_size(tag) - commit->begin;
for (lfs_off_t i = 0; i < size; i++) {
// leave it up to caching to make this efficient
uint8_t dat;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, size-i,
commit->block, commit->begin+i, &dat, 1);
if (err) {
return err;
}
crc = lfs_crc(crc, &dat, 1);
}
if (err) {
return err;
}
if (crc != commit->crc) {
return LFS_ERR_CORRUPT;
}
return 0;
}
static int lfs_dir_alloc(lfs_t *lfs, lfs_mdir_t *dir) {
// allocate pair of dir blocks (backwards, so we write block 1 first)
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &dir->pair[(i+1)%2]);
if (err) {
return err;
}
}
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, sizeof(dir->rev),
dir->pair[0], 0, &dir->rev, sizeof(dir->rev));
if (err) {
return err;
}
dir->rev = lfs_fromle32(dir->rev);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
// set defaults
dir->off = sizeof(dir->rev);
dir->etag = 0xffffffff;
dir->count = 0;
dir->tail[0] = 0xffffffff;
dir->tail[1] = 0xffffffff;
dir->erased = false;
dir->split = false;
// don't write out yet, let caller take care of that
return 0;
}
static int lfs_dir_drop(lfs_t *lfs, lfs_mdir_t *dir, const lfs_mdir_t *tail) {
// steal tail
dir->tail[0] = tail->tail[0];
dir->tail[1] = tail->tail[1];
dir->split = tail->split;
// steal state
int err = lfs_dir_getglobals(lfs, tail, &lfs->locals);
if (err) {
return err;
}
// update pred's tail
return lfs_dir_commit(lfs, dir,
LFS_MKATTR(LFS_TYPE_TAIL + dir->split,
0x1ff, dir->tail, sizeof(dir->tail),
NULL));
}
static int lfs_dir_compact(lfs_t *lfs,
lfs_mdir_t *dir, const struct lfs_mattr *attrs,
lfs_mdir_t *source, uint16_t begin, uint16_t end) {
// save some state in case block is bad
const lfs_block_t oldpair[2] = {dir->pair[1], dir->pair[0]};
bool relocated = false;
// There's nothing special about our global delta, so feed it back
// into the global global delta
int err = lfs_dir_getglobals(lfs, dir, &lfs->locals);
if (err) {
return err;
}
// begin loop to commit compaction to blocks until a compact sticks
while (true) {
// setup compaction
bool splitted = false;
bool exhausted = false;
bool overcompacting = false;
struct lfs_commit commit;
commit.block = dir->pair[1];
commit.ack = 0;
commit:
// setup erase state
exhausted = false;
dir->count = end - begin;
int16_t ackid = -1;
// setup commit state
commit.off = 0;
commit.crc = 0xffffffff;
commit.ptag = 0xffffffff;
// space is complicated, we need room for tail, crc, globals,
// cleanup delete, and we cap at half a block to give room
// for metadata updates
commit.begin = 0;
commit.end = lfs->cfg->block_size - 38;
if (!overcompacting) {
commit.end = lfs_min(commit.end,
lfs_alignup(lfs->cfg->block_size/2, lfs->cfg->prog_size));
}
if (!splitted) {
// increment revision count
dir->rev += 1;
if (lfs->cfg->block_cycles &&
dir->rev % lfs->cfg->block_cycles == 0) {
if (lfs_pair_cmp(dir->pair,
(const lfs_block_t[2]){0, 1}) == 0) {
// we're writing too much to the superblock,
// should we expand?
lfs_stag_t res = lfs_fs_size(lfs);
if (res < 0) {
return res;
}
// do we have enough space to expand?
if (res < lfs->cfg->block_count/2) {
LFS_DEBUG("Expanding superblock at rev %"PRIu32,
dir->rev);
exhausted = true;
goto split;
}
} else {
// we're writing too much, time to relocate
exhausted = true;
goto relocate;
}
}
// erase block to write to
err = lfs_bd_erase(lfs, dir->pair[1]);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
// write out header
uint32_t rev = lfs_tole32(dir->rev);
err = lfs_commit_prog(lfs, &commit, &rev, sizeof(rev));
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// commit with a move
for (uint16_t id = begin; id < end || commit.off < commit.ack; id++) {
for (int pass = 0; pass < 2; pass++) {
err = lfs_commit_move(lfs, &commit, pass,
0x003fe000, LFS_MKTAG(0, id, 0),
-LFS_MKTAG(0, begin, 0),
source, attrs);
if (err && !(splitted && !overcompacting &&
err == LFS_ERR_NOSPC)) {
if (!overcompacting && err == LFS_ERR_NOSPC) {
goto split;
} else if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
ackid = id;
}
// reopen reserved space at the end
commit.end = lfs->cfg->block_size - 8;
if (ackid >= end) {
// extra garbage attributes were written out during split,
// need to clean up
err = lfs_commit_attr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_DELETE, ackid, 0), NULL);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
if (!relocated && !lfs_global_iszero(&lfs->locals)) {
// commit any globals, unless we're relocating,
// in which case our parent will steal our globals
err = lfs_commit_globals(lfs, &commit, &lfs->locals);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
if (!lfs_pair_isnull(dir->tail)) {
// commit tail, which may be new after last size check
lfs_pair_tole32(dir->tail);
err = lfs_commit_attr(lfs, &commit,
LFS_MKTAG(LFS_TYPE_TAIL + dir->split,
0x1ff, sizeof(dir->tail)), dir->tail);
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
}
err = lfs_commit_crc(lfs, &commit, true);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// successful compaction, swap dir pair to indicate most recent
lfs_pair_swap(dir->pair);
dir->off = commit.off;
dir->etag = commit.ptag;
dir->erased = true;
break;
split:
// commit no longer fits, need to split dir,
// drop caches and create tail
splitted = !exhausted;
if (lfs->pcache.block != 0xffffffff) {
commit.ack -= lfs->pcache.size;
lfs_cache_drop(lfs, &lfs->pcache);
}
if (!exhausted && ackid < 0) {
// If we can't fit in this block, we won't fit in next block
return LFS_ERR_NOSPC;
}
lfs_mdir_t tail;
err = lfs_dir_alloc(lfs, &tail);
if (err) {
if (err == LFS_ERR_NOSPC) {
// No space to expand? Try overcompacting
overcompacting = true;
goto commit;
}
return err;
}
tail.split = dir->split;
tail.tail[0] = dir->tail[0];
tail.tail[1] = dir->tail[1];
err = lfs_dir_compact(lfs, &tail, attrs, source, ackid+1, end);
if (err) {
return err;
}
end = ackid+1;
dir->tail[0] = tail.pair[0];
dir->tail[1] = tail.pair[1];
dir->split = true;
if (exhausted) {
lfs->root[0] = tail.pair[0];
lfs->root[1] = tail.pair[1];
}
goto commit;
relocate:
// commit was corrupted, drop caches and prepare to relocate block
relocated = true;
lfs_cache_drop(lfs, &lfs->pcache);
if (!exhausted) {
LFS_DEBUG("Bad block at %"PRIu32, dir->pair[1]);
}
// can't relocate superblock, filesystem is now frozen
if (lfs_pair_cmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
LFS_WARN("Superblock %"PRIu32" has become unwritable", oldpair[1]);
return LFS_ERR_NOSPC;
}
// relocate half of pair
err = lfs_alloc(lfs, &dir->pair[1]);
if (err && (err != LFS_ERR_NOSPC && !exhausted)) {
return err;
}
continue;
}
if (!relocated) {
// successful commit, update globals
lfs_global_zero(&lfs->locals);
} else {
// update references if we relocated
LFS_DEBUG("Relocating %"PRIu32" %"PRIu32" to %"PRIu32" %"PRIu32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
err = lfs_fs_relocate(lfs, oldpair, dir->pair);
if (err) {
return err;
}
}
return 0;
}
static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
const struct lfs_mattr *attrs) {
struct lfs_mattr cancelattr;
struct lfs_globals cancels;
lfs_global_zero(&cancels);
if (lfs->globals.hasmove &&
lfs_pair_cmp(dir->pair, lfs->globals.pair) == 0) {
// Wait, we have the move? Just cancel this out here
// We need to, or else the move can become outdated
cancelattr.tag = LFS_MKTAG(LFS_TYPE_DELETE, lfs->globals.id, 0);
cancelattr.next = attrs;
attrs = &cancelattr;
cancels.hasmove = lfs->globals.hasmove;
cancels.pair[0] = lfs->globals.pair[0];
cancels.pair[1] = lfs->globals.pair[1];
cancels.id = lfs->globals.id;
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->locals, &cancels);
lfs_global_tole32(&lfs->locals);
}
// calculate new directory size
lfs_tag_t deletetag = 0xffffffff;
lfs_tag_t createtag = 0xffffffff;
int attrcount = 0;
for (const struct lfs_mattr *a = attrs; a; a = a->next) {
if (lfs_tag_subtype(a->tag) == LFS_TYPE_NAME) {
dir->count += 1;
createtag = a->tag;
} else if (lfs_tag_subtype(a->tag) == LFS_TYPE_DELETE) {
LFS_ASSERT(dir->count > 0);
dir->count -= 1;
deletetag = a->tag;
if (dir->count == 0) {
// should we actually drop the directory block?
lfs_mdir_t pdir;
int err = lfs_fs_pred(lfs, dir->pair, &pdir);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err != LFS_ERR_NOENT && pdir.split) {
return lfs_dir_drop(lfs, &pdir, dir);
}
}
}
attrcount += 1;
}
while (true) {
if (!dir->erased) {
goto compact;
}
// try to commit
struct lfs_commit commit = {
.block = dir->pair[0],
.off = dir->off,
.crc = 0xffffffff,
.ptag = dir->etag,
.begin = dir->off,
.end = lfs->cfg->block_size - 8,
.ack = 0,
};
// iterate over commits backwards, this lets us "append" commits
for (int i = 0; i < attrcount; i++) {
const struct lfs_mattr *a = attrs;
for (int j = 0; j < attrcount-i-1; j++) {
a = a->next;
}
lfs_pair_tole32(dir->tail);
int err = lfs_commit_attr(lfs, &commit, a->tag, a->buffer);
lfs_pair_fromle32(dir->tail);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
}
// commit any global diffs if we have any
if (!lfs_global_iszero(&lfs->locals)) {
struct lfs_globals locals = lfs->locals;
int err = lfs_dir_getglobals(lfs, dir, &locals);
if (err) {
return err;
}
err = lfs_commit_globals(lfs, &commit, &locals);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
}
// finalize commit with the crc
int err = lfs_commit_crc(lfs, &commit, false);
if (err) {
if (err == LFS_ERR_NOSPC || err == LFS_ERR_CORRUPT) {
goto compact;
}
return err;
}
// successful commit, update dir
dir->off = commit.off;
dir->etag = commit.ptag;
// successful commit, update globals
lfs_global_zero(&lfs->locals);
break;
compact:
// fall back to compaction
lfs_cache_drop(lfs, &lfs->pcache);
err = lfs_dir_compact(lfs, dir, attrs, dir, 0, dir->count);
if (err) {
return err;
}
break;
}
// update globals that are affected
lfs_global_xor(&lfs->globals, &cancels);
// update any directories that are affected
lfs_mdir_t copy = *dir;
// two passes, once for things that aren't us, and one
// for things that are
for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(d->m.pair, copy.pair) == 0) {
d->m = *dir;
if (d->id == lfs_tag_id(deletetag)) {
d->m.pair[0] = 0xffffffff;
d->m.pair[1] = 0xffffffff;
} else if (d->id > lfs_tag_id(deletetag)) {
d->id -= 1;
if (d->type == LFS_TYPE_DIR) {
((lfs_dir_t*)d)->pos -= 1;
}
} else if (&d->m != dir && d->id >= lfs_tag_id(createtag)) {
d->id += 1;
if (d->type == LFS_TYPE_DIR) {
((lfs_dir_t*)d)->pos += 1;
}
}
while (d->id >= d->m.count && d->m.split) {
// we split and id is on tail now
d->id -= d->m.count;
int err = lfs_dir_fetch(lfs, &d->m, d->m.tail);
if (err) {
return err;
}
}
}
}
return 0;
}
/// Top level directory operations ///
int lfs_mkdir(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
lfs_mdir_t cwd;
uint16_t id;
err = lfs_dir_find(lfs, &cwd, &path, &id);
if (!(err == LFS_ERR_NOENT && id != 0x1ff)) {
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;
}
dir.tail[0] = cwd.tail[0];
dir.tail[1] = cwd.tail[1];
err = lfs_dir_commit(lfs, &dir, NULL);
if (err) {
return err;
}
// get next slot and commit
cwd.tail[0] = dir.pair[0];
cwd.tail[1] = dir.pair[1];
lfs_pair_tole32(dir.pair);
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x1ff, cwd.tail, sizeof(cwd.tail),
LFS_MKATTR(LFS_TYPE_DIRSTRUCT, id, dir.pair, sizeof(dir.pair),
LFS_MKATTR(LFS_TYPE_DIR, id, path, nlen,
NULL))));
lfs_pair_fromle32(dir.pair);
if (err) {
return err;
}
return 0;
}
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
lfs_stag_t tag = lfs_dir_find(lfs, &dir->m, &path, NULL);
if (tag < 0) {
return tag;
}
if (lfs_tag_type(tag) != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
lfs_block_t pair[2];
if (lfs_tag_id(tag) == 0x1ff) {
// 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, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
}
// fetch first pair
int err = lfs_dir_fetch(lfs, &dir->m, pair);
if (err) {
return err;
}
// setup entry
dir->head[0] = dir->m.pair[0];
dir->head[1] = dir->m.pair[1];
dir->id = 0;
dir->pos = 0;
// add to list of mdirs
dir->type = LFS_TYPE_DIR;
dir->next = (lfs_dir_t*)lfs->mlist;
lfs->mlist = (struct lfs_mlist*)dir;
return 0;
}
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
// remove from list of mdirs
for (struct lfs_mlist **p = &lfs->mlist; *p; p = &(*p)->next) {
if (*p == (struct lfs_mlist*)dir) {
*p = (*p)->next;
break;
}
}
return 0;
}
int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info) {
memset(info, 0, sizeof(*info));
// special offset for '.' and '..'
if (dir->pos == 0) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, ".");
dir->pos += 1;
return 1;
} else if (dir->pos == 1) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, "..");
dir->pos += 1;
return 1;
}
while (true) {
if (dir->id == dir->m.count) {
if (!dir->m.split) {
return false;
}
int err = lfs_dir_fetch(lfs, &dir->m, dir->m.tail);
if (err) {
return err;
}
dir->id = 0;
}
int err = lfs_dir_getinfo(lfs, &dir->m, dir->id, info);
if (err && err != LFS_ERR_NOENT) {
return err;
}
dir->id += 1;
if (err != LFS_ERR_NOENT) {
break;
}
}
dir->pos += 1;
return true;
}
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
// simply walk from head dir
int err = lfs_dir_rewind(lfs, dir);
if (err) {
return err;
}
// first two for ./..
dir->pos = lfs_min(2, off);
off -= dir->pos;
while (off != 0) {
dir->id = lfs_min(dir->m.count, off);
dir->pos += dir->id;
off -= dir->id;
if (dir->id == dir->m.count) {
if (!dir->m.split) {
return LFS_ERR_INVAL;
}
err = lfs_dir_fetch(lfs, &dir->m, dir->m.tail);
if (err) {
return err;
}
}
}
return 0;
}
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir) {
(void)lfs;
return dir->pos;
}
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir) {
// reload the head dir
int err = lfs_dir_fetch(lfs, &dir->m, dir->head);
if (err) {
return err;
}
dir->m.pair[0] = dir->head[0];
dir->m.pair[1] = dir->head[1];
dir->id = 0;
dir->pos = 0;
return 0;
}
/// File index list operations ///
static int lfs_ctz_index(lfs_t *lfs, lfs_off_t *off) {
lfs_off_t size = *off;
lfs_off_t b = lfs->cfg->block_size - 2*4;
lfs_off_t i = size / b;
if (i == 0) {
return 0;
}
i = (size - 4*(lfs_popc(i-1)+2)) / b;
*off = size - b*i - 4*lfs_popc(i);
return i;
}
static int lfs_ctz_find(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
if (size == 0) {
*block = 0xffffffff;
*off = 0;
return 0;
}
lfs_off_t current = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
lfs_off_t target = lfs_ctz_index(lfs, &pos);
while (current > target) {
lfs_size_t skip = lfs_min(
lfs_npw2(current-target+1) - 1,
lfs_ctz(current));
int err = lfs_bd_read(lfs,
pcache, rcache, sizeof(head),
head, 4*skip, &head, sizeof(head));
head = lfs_fromle32(head);
if (err) {
return err;
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
current -= 1 << skip;
}
*block = head;
*off = pos;
return 0;
}
static int lfs_ctz_extend(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
lfs_block_t *block, lfs_off_t *off) {
while (true) {
// go ahead and grab a block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
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_bd_read(lfs,
NULL, rcache, size-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 = 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_bd_prog(lfs, pcache, rcache, true,
nblock, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
if (i != skips-1) {
err = lfs_bd_read(lfs,
NULL, rcache, sizeof(head),
head, 4*i, &head, sizeof(head));
head = lfs_fromle32(head);
if (err) {
return err;
}
}
LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
}
*block = nblock;
*off = 4*skips;
return 0;
relocate:
LFS_DEBUG("Bad block at %"PRIu32, nblock);
// just clear cache and try a new block
lfs_cache_drop(lfs, pcache);
}
}
static int lfs_ctz_traverse(lfs_t *lfs,
const lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t head, lfs_size_t size,
int (*cb)(void*, lfs_block_t), void *data) {
if (size == 0) {
return 0;
}
lfs_off_t index = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
while (true) {
int err = cb(data, head);
if (err) {
return err;
}
if (index == 0) {
return 0;
}
lfs_block_t heads[2];
int count = 2 - (index & 1);
err = lfs_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 ///
int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags,
const struct lfs_file_config *cfg) {
// deorphan if we haven't yet, needed at most once after poweron
if ((flags & 3) != LFS_O_RDONLY) {
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
}
// setup simple file details
int err;
file->cfg = cfg;
file->flags = flags;
file->pos = 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 != 0x1ff)) {
err = tag;
goto cleanup;
}
// get id, add to list of mdirs to catch update changes
file->type = LFS_TYPE_REG;
file->next = (lfs_file_t*)lfs->mlist;
lfs->mlist = (struct lfs_mlist*)file;
if (tag == LFS_ERR_NOENT) {
if (!(flags & LFS_O_CREAT)) {
err = LFS_ERR_NOENT;
goto cleanup;
}
// check that name fits
lfs_size_t nlen = strlen(path);
if (nlen > lfs->name_max) {
err = LFS_ERR_NAMETOOLONG;
goto cleanup;
}
// get next slot and create entry to remember name
err = lfs_dir_commit(lfs, &file->m,
LFS_MKATTR(LFS_TYPE_INLINESTRUCT, file->id, NULL, 0,
LFS_MKATTR(LFS_TYPE_REG, file->id, path, nlen,
NULL)));
if (err) {
err = LFS_ERR_NAMETOOLONG;
goto cleanup;
}
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, 0, 0);
} else if (flags & LFS_O_EXCL) {
err = LFS_ERR_EXIST;
goto cleanup;
} else if (lfs_tag_type(tag) != LFS_TYPE_REG) {
err = LFS_ERR_ISDIR;
goto cleanup;
} else if (flags & LFS_O_TRUNC) {
// truncate if requested
tag = LFS_MKTAG(LFS_TYPE_INLINESTRUCT, file->id, 0);
file->flags |= LFS_F_DIRTY;
} else {
// try to load what's on disk, if it's inlined we'll fix it later
tag = lfs_dir_get(lfs, &file->m, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, file->id, 8), &file->ctz);
if (tag < 0) {
err = tag;
goto cleanup;
}
lfs_ctz_fromle32(&file->ctz);
}
// fetch attrs
for (const struct lfs_attr *a = file->cfg->attrs; a; a = a->next) {
if ((file->flags & 3) != LFS_O_WRONLY) {
lfs_stag_t res = lfs_dir_get(lfs, &file->m, 0x7fffe000,
LFS_MKTAG(0x100 | a->type, file->id, a->size), a->buffer);
if (res < 0 && res != LFS_ERR_NOENT) {
err = res;
goto cleanup;
}
}
if ((file->flags & 3) != LFS_O_RDONLY) {
if (a->size > lfs->attr_max) {
err = LFS_ERR_NOSPC;
goto cleanup;
}
file->flags |= LFS_F_DIRTY;
}
}
// allocate buffer if needed
if (file->cfg->buffer) {
file->cache.buffer = file->cfg->buffer;
} else {
file->cache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!file->cache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// zero to avoid information leak
lfs_cache_zero(lfs, &file->cache);
if (lfs_tag_type(tag) == LFS_TYPE_INLINESTRUCT) {
// load inline files
file->ctz.head = 0xfffffffe;
file->ctz.size = lfs_tag_size(tag);
file->flags |= LFS_F_INLINE;
file->cache.block = file->ctz.head;
file->cache.off = 0;
file->cache.size = lfs->cfg->cache_size;
// don't always read (may be new/trunc file)
if (file->ctz.size > 0) {
lfs_stag_t res = lfs_dir_get(lfs, &file->m, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, file->id, file->ctz.size),
file->cache.buffer);
if (res < 0) {
err = res;
goto cleanup;
}
}
}
return 0;
cleanup:
// clean up lingering resources
file->flags |= LFS_F_ERRED;
lfs_file_close(lfs, file);
return err;
}
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags) {
static const struct lfs_file_config defaults = {0};
return lfs_file_opencfg(lfs, file, path, flags, &defaults);
}
int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_sync(lfs, file);
// remove from list of mdirs
for (struct lfs_mlist **p = &lfs->mlist; *p; p = &(*p)->next) {
if (*p == (struct lfs_mlist*)file) {
*p = (*p)->next;
break;
}
}
// clean up memory
if (!file->cfg->buffer) {
lfs_free(file->cache.buffer);
}
return err;
}
static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
while (true) {
// just relocate what exists into new block
lfs_block_t nblock;
int err = lfs_alloc(lfs, &nblock);
if (err) {
return err;
}
err = lfs_bd_erase(lfs, nblock);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
}
return err;
}
// either read from dirty cache or disk
for (lfs_off_t i = 0; i < file->off; i++) {
uint8_t data;
err = lfs_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;
return 0;
relocate:
LFS_DEBUG("Bad block at %"PRIu32, nblock);
// just clear cache and try a new block
lfs_cache_drop(lfs, &lfs->pcache);
}
}
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
if (file->flags & LFS_F_READING) {
file->flags &= ~LFS_F_READING;
}
if (file->flags & LFS_F_WRITING) {
lfs_off_t pos = file->pos;
if (!(file->flags & LFS_F_INLINE)) {
// copy over anything after current branch
lfs_file_t orig = {
.ctz.head = file->ctz.head,
.ctz.size = file->ctz.size,
.flags = LFS_O_RDONLY,
.pos = file->pos,
.cache = lfs->rcache,
};
lfs_cache_drop(lfs, &lfs->rcache);
while (file->pos < file->ctz.size) {
// copy over a byte at a time, leave it up to caching
// to make this efficient
uint8_t data;
lfs_ssize_t res = lfs_file_read(lfs, &orig, &data, 1);
if (res < 0) {
return res;
}
res = lfs_file_write(lfs, file, &data, 1);
if (res < 0) {
return res;
}
// keep our reference to the rcache in sync
if (lfs->rcache.block != 0xffffffff) {
lfs_cache_drop(lfs, &orig.cache);
lfs_cache_drop(lfs, &lfs->rcache);
}
}
// write out what we have
while (true) {
int err = lfs_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 %"PRIu32, file->block);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
}
} else {
file->ctz.size = lfs_max(file->pos, file->ctz.size);
}
// actual file updates
file->ctz.head = file->block;
file->ctz.size = file->pos;
file->flags &= ~LFS_F_WRITING;
file->flags |= LFS_F_DIRTY;
file->pos = pos;
}
return 0;
}
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
while (true) {
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
if ((file->flags & LFS_F_DIRTY) &&
!(file->flags & LFS_F_ERRED) &&
!lfs_pair_isnull(file->m.pair)) {
// update dir entry
uint16_t type;
const void *buffer;
lfs_size_t size;
struct lfs_ctz ctz;
if (file->flags & LFS_F_INLINE) {
// inline the whole file
type = LFS_TYPE_INLINESTRUCT;
buffer = file->cache.buffer;
size = file->ctz.size;
} else {
// update the ctz reference
type = LFS_TYPE_CTZSTRUCT;
// copy ctz so alloc will work during a relocate
ctz = file->ctz;
lfs_ctz_tole32(&ctz);
buffer = &ctz;
size = sizeof(ctz);
}
// commit file data and attributes
err = lfs_dir_commit(lfs, &file->m,
LFS_MKATTR(LFS_FROM_USERATTRS,
file->id, file->cfg->attrs, 0,
LFS_MKATTR(type, file->id, buffer, size,
NULL)));
if (err) {
if (err == LFS_ERR_NOSPC && (file->flags & LFS_F_INLINE)) {
goto relocate;
}
return err;
}
file->flags &= ~LFS_F_DIRTY;
}
return 0;
relocate:
// inline file doesn't fit anymore
file->block = 0xfffffffe;
file->off = file->pos;
lfs_alloc_ack(lfs);
err = lfs_file_relocate(lfs, file);
if (err) {
return err;
}
file->flags &= ~LFS_F_INLINE;
file->flags |= LFS_F_WRITING;
}
}
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_WRONLY) {
return LFS_ERR_BADF;
}
if (file->flags & LFS_F_WRITING) {
// flush out any writes
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if (file->pos >= file->ctz.size) {
// eof if past end
return 0;
}
size = lfs_min(size, file->ctz.size - file->pos);
nsize = size;
while (nsize > 0) {
// check if we need a new block
if (!(file->flags & LFS_F_READING) ||
file->off == lfs->cfg->block_size) {
if (!(file->flags & LFS_F_INLINE)) {
int err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
file->pos, &file->block, &file->off);
if (err) {
return err;
}
} else {
file->block = 0xfffffffe;
file->off = file->pos;
}
file->flags |= LFS_F_READING;
}
// read as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
int err = lfs_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;
}
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
if (file->flags & LFS_F_READING) {
// drop any reads
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if ((file->flags & LFS_O_APPEND) && file->pos < file->ctz.size) {
file->pos = file->ctz.size;
}
if (!(file->flags & LFS_F_WRITING) && file->pos > file->ctz.size) {
// fill with zeros
lfs_off_t pos = file->pos;
file->pos = file->ctz.size;
while (file->pos < pos) {
lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
}
if ((file->flags & LFS_F_INLINE) &&
file->pos + nsize > lfs->inline_max) {
// inline file doesn't fit anymore
file->block = 0xfffffffe;
file->off = file->pos;
lfs_alloc_ack(lfs);
int err = lfs_file_relocate(lfs, file);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
file->flags &= ~LFS_F_INLINE;
file->flags |= LFS_F_WRITING;
}
while (nsize > 0) {
// check if we need a new block
if (!(file->flags & LFS_F_WRITING) ||
file->off == lfs->cfg->block_size) {
if (!(file->flags & LFS_F_INLINE)) {
if (!(file->flags & LFS_F_WRITING) && file->pos > 0) {
// find out which block we're extending from
int err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
file->pos-1, &file->block, &file->off);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
// mark cache as dirty since we may have read data into it
lfs_cache_zero(lfs, &file->cache);
}
// extend file with new blocks
lfs_alloc_ack(lfs);
int err = lfs_ctz_extend(lfs, &file->cache, &lfs->rcache,
file->block, file->pos,
&file->block, &file->off);
if (err) {
file->flags |= LFS_F_ERRED;
return err;
}
} else {
file->block = 0xfffffffe;
file->off = file->pos;
}
file->flags |= LFS_F_WRITING;
}
// program as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
while (true) {
int err = lfs_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);
}
file->flags &= ~LFS_F_ERRED;
return size;
}
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
// write out everything beforehand, may be noop if rdonly
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// update pos
if (whence == LFS_SEEK_SET) {
file->pos = off;
} else if (whence == LFS_SEEK_CUR) {
if (off < 0 && (lfs_off_t)-off > file->pos) {
return LFS_ERR_INVAL;
}
file->pos = file->pos + off;
} else if (whence == LFS_SEEK_END) {
if (off < 0 && (lfs_off_t)-off > file->ctz.size) {
return LFS_ERR_INVAL;
}
file->pos = file->ctz.size + off;
}
return file->pos;
}
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_BADF;
}
lfs_off_t oldsize = lfs_file_size(lfs, file);
if (size < oldsize) {
// need to flush since directly changing metadata
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// lookup new head in ctz skip list
err = lfs_ctz_find(lfs, NULL, &file->cache,
file->ctz.head, file->ctz.size,
size, &file->ctz.head, &(lfs_off_t){0});
if (err) {
return err;
}
file->ctz.size = size;
file->flags |= LFS_F_DIRTY;
} else if (size > oldsize) {
lfs_off_t pos = file->pos;
// flush+seek if not already at end
if (file->pos != oldsize) {
int err = lfs_file_seek(lfs, file, 0, LFS_SEEK_END);
if (err < 0) {
return err;
}
}
// fill with zeros
while (file->pos < size) {
lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
if (res < 0) {
return res;
}
}
// restore pos
int err = lfs_file_seek(lfs, file, pos, LFS_SEEK_SET);
if (err < 0) {
return err;
}
}
return 0;
}
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
return file->pos;
}
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file) {
lfs_soff_t res = lfs_file_seek(lfs, file, 0, LFS_SEEK_SET);
if (res < 0) {
return res;
}
return 0;
}
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
(void)lfs;
if (file->flags & LFS_F_WRITING) {
return lfs_max(file->pos, file->ctz.size);
} else {
return file->ctz.size;
}
}
/// General fs operations ///
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0) {
return tag;
}
return lfs_dir_getinfo(lfs, &cwd, lfs_tag_id(tag), info);
}
int lfs_remove(lfs_t *lfs, const char *path) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
lfs_mdir_t cwd;
lfs_stag_t tag = lfs_dir_find(lfs, &cwd, &path, NULL);
if (tag < 0) {
return tag;
}
lfs_mdir_t dir;
if (lfs_tag_type(tag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t pair[2];
lfs_stag_t res = lfs_dir_get(lfs, &cwd, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, lfs_tag_id(tag), 8), pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
err = lfs_dir_fetch(lfs, &dir, pair);
if (err) {
return err;
}
if (dir.count > 0 || dir.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
lfs_global_orphans(lfs, +1);
}
// delete the entry
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_DELETE, lfs_tag_id(tag), NULL, 0,
NULL));
if (err) {
return err;
}
if (lfs_tag_type(tag) == LFS_TYPE_DIR) {
// fix orphan
lfs_global_orphans(lfs, -1);
err = lfs_fs_pred(lfs, dir.pair, &cwd);
if (err) {
return err;
}
err = lfs_dir_drop(lfs, &cwd, &dir);
if (err) {
return err;
}
}
return 0;
}
int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
// deorphan if we haven't yet, needed at most once after poweron
int err = lfs_fs_forceconsistency(lfs);
if (err) {
return err;
}
// find old entry
lfs_mdir_t oldcwd;
lfs_stag_t oldtag = lfs_dir_find(lfs, &oldcwd, &oldpath, NULL);
if (oldtag < 0) {
return oldtag;
}
// find new entry
lfs_mdir_t newcwd;
uint16_t newid;
lfs_stag_t prevtag = lfs_dir_find(lfs, &newcwd, &newpath, &newid);
if (prevtag < 0 && !(prevtag == LFS_ERR_NOENT && newid != 0x1ff)) {
return err;
}
lfs_mdir_t prevdir;
if (prevtag == LFS_ERR_NOENT) {
// check that name fits
lfs_size_t nlen = strlen(newpath);
if (nlen > lfs->name_max) {
return LFS_ERR_NAMETOOLONG;
}
} else if (lfs_tag_type(prevtag) != lfs_tag_type(oldtag)) {
return LFS_ERR_ISDIR;
} else if (lfs_tag_type(prevtag) == LFS_TYPE_DIR) {
// must be empty before removal
lfs_block_t prevpair[2];
lfs_stag_t res = lfs_dir_get(lfs, &newcwd, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, newid, 8), prevpair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(prevpair);
// must be empty before removal
err = lfs_dir_fetch(lfs, &prevdir, prevpair);
if (err) {
return err;
}
if (prevdir.count > 0 || prevdir.split) {
return LFS_ERR_NOTEMPTY;
}
// mark fs as orphaned
lfs_global_orphans(lfs, +1);
}
// create move to fix later
lfs_global_move(lfs, true, oldcwd.pair, lfs_tag_id(oldtag));
// move over all attributes
err = lfs_dir_commit(lfs, &newcwd,
LFS_MKATTR(LFS_FROM_MOVE, newid, &oldcwd, lfs_tag_id(oldtag),
LFS_MKATTR(lfs_tag_type(oldtag), newid, newpath, strlen(newpath),
(prevtag != LFS_ERR_NOENT)
? LFS_MKATTR(LFS_TYPE_DELETE, newid, NULL, 0, NULL)
: NULL)));
if (err) {
return err;
}
// let commit clean up after move (if we're different! otherwise move
// logic already fixed it for us)
if (lfs_pair_cmp(oldcwd.pair, newcwd.pair) != 0) {
err = lfs_dir_commit(lfs, &oldcwd, NULL);
if (err) {
return err;
}
}
if (prevtag != LFS_ERR_NOENT && lfs_tag_type(prevtag) == LFS_TYPE_DIR) {
// fix orphan
lfs_global_orphans(lfs, -1);
err = lfs_fs_pred(lfs, prevdir.pair, &newcwd);
if (err) {
return err;
}
err = lfs_dir_drop(lfs, &newcwd, &prevdir);
if (err) {
return err;
}
}
return 0;
}
lfs_ssize_t lfs_getattr(lfs_t *lfs, const char *path,
uint8_t type, void *buffer, lfs_size_t size) {
lfs_mdir_t cwd;
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 == 0x1ff) {
// 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, 0x7fffe000,
LFS_MKTAG(0x100 | 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);
}
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 == 0x1ff) {
// 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_MKATTR(0x100 | type, id, buffer, size,
NULL));
}
int lfs_setattr(lfs_t *lfs, const char *path,
uint8_t type, const void *buffer, lfs_size_t size) {
if (size > lfs->attr_max) {
return LFS_ERR_NOSPC;
}
return lfs_commitattr(lfs, path, type, buffer, size);
}
int lfs_removeattr(lfs_t *lfs, const char *path, uint8_t type) {
return lfs_commitattr(lfs, path, type, NULL, 0x1fff);
}
/// Filesystem operations ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
lfs->cfg = cfg;
int err = 0;
// check that block size is a multiple of cache size is a multiple
// of prog and read sizes
LFS_ASSERT(lfs->cfg->cache_size % lfs->cfg->read_size == 0);
LFS_ASSERT(lfs->cfg->cache_size % lfs->cfg->prog_size == 0);
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->cache_size == 0);
// check that the block size is large enough to fit ctz pointers
LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
<= lfs->cfg->block_size);
// setup read cache
if (lfs->cfg->read_buffer) {
lfs->rcache.buffer = lfs->cfg->read_buffer;
} else {
lfs->rcache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!lfs->rcache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// setup program cache
if (lfs->cfg->prog_buffer) {
lfs->pcache.buffer = lfs->cfg->prog_buffer;
} else {
lfs->pcache.buffer = lfs_malloc(lfs->cfg->cache_size);
if (!lfs->pcache.buffer) {
err = LFS_ERR_NOMEM;
goto cleanup;
}
}
// zero to avoid information leaks
lfs_cache_zero(lfs, &lfs->rcache);
lfs_cache_zero(lfs, &lfs->pcache);
// setup lookahead, must be multiple of 32-bits
LFS_ASSERT(lfs->cfg->lookahead_size % 4 == 0);
LFS_ASSERT(lfs->cfg->lookahead_size > 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->inline_max <= LFS_INLINE_MAX);
LFS_ASSERT(lfs->cfg->inline_max <= lfs->cfg->cache_size);
lfs->inline_max = lfs->cfg->inline_max;
if (!lfs->inline_max) {
lfs->inline_max = lfs_min(LFS_INLINE_MAX, lfs->cfg->cache_size);
}
LFS_ASSERT(lfs->cfg->attr_max <= LFS_ATTR_MAX);
lfs->attr_max = lfs->cfg->attr_max;
if (!lfs->attr_max) {
lfs->attr_max = LFS_ATTR_MAX;
}
// setup default state
lfs->root[0] = 0xffffffff;
lfs->root[1] = 0xffffffff;
lfs->mlist = NULL;
lfs->seed = 0;
lfs_global_zero(&lfs->globals);
lfs_global_zero(&lfs->locals);
return 0;
cleanup:
lfs_deinit(lfs);
return err;
}
static int lfs_deinit(lfs_t *lfs) {
// free allocated memory
if (!lfs->cfg->read_buffer) {
lfs_free(lfs->rcache.buffer);
}
if (!lfs->cfg->prog_buffer) {
lfs_free(lfs->pcache.buffer);
}
if (!lfs->cfg->lookahead_buffer) {
lfs_free(lfs->free.buffer);
}
return 0;
}
int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// create free lookahead
memset(lfs->free.buffer, 0, lfs->cfg->lookahead_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 = {
.magic = {"littlefs"},
.version = LFS_DISK_VERSION,
.block_size = lfs->cfg->block_size,
.block_count = lfs->cfg->block_count,
.name_max = lfs->name_max,
.inline_max = lfs->inline_max,
.attr_max = lfs->attr_max,
};
lfs_superblock_tole32(&superblock);
err = lfs_dir_commit(lfs, &root,
LFS_MKATTR(LFS_TYPE_SUPERBLOCK, 0, &superblock, sizeof(superblock),
NULL));
if (err) {
goto cleanup;
}
// sanity check that fetch works
err = lfs_dir_fetch(lfs, &root, (const lfs_block_t[2]){0, 1});
if (err) {
goto cleanup;
}
cleanup:
lfs_deinit(lfs);
return err;
}
int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// scan directory blocks for superblock and any global updates
lfs_mdir_t dir = {.tail = {0, 1}};
while (!lfs_pair_isnull(dir.tail)) {
// fetch next block in tail list
lfs_stag_t tag = lfs_dir_fetchmatch(lfs, &dir, dir.tail, 0x7fc00000,
LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 0, 8),
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, 0x7f800000,
LFS_MKTAG(LFS_TYPE_SUPERBLOCK, 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 %"PRIu32".%"PRIu32,
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.inline_max) {
if (superblock.inline_max > lfs->inline_max) {
LFS_ERROR("Unsupported inline_max (%"PRIu32" > %"PRIu32")",
superblock.inline_max, lfs->inline_max);
err = LFS_ERR_INVAL;
goto cleanup;
}
lfs->inline_max = superblock.inline_max;
}
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;
}
}
// has globals?
err = lfs_dir_getglobals(lfs, &dir, &lfs->locals);
if (err) {
return err;
}
}
// update littlefs with globals
lfs_global_fromle32(&lfs->locals);
lfs_global_xor(&lfs->globals, &lfs->locals);
lfs_global_zero(&lfs->locals);
if (lfs->globals.hasmove) {
LFS_DEBUG("Found move %"PRIu32" %"PRIu32" %"PRIu32,
lfs->globals.pair[0], lfs->globals.pair[1], lfs->globals.id);
}
// setup free lookahead
lfs->free.off = lfs->seed % lfs->cfg->block_size;
lfs->free.size = 0;
lfs->free.i = 0;
lfs_alloc_ack(lfs);
return 0;
cleanup:
lfs_unmount(lfs);
return err;
}
int lfs_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// Filesystem filesystem operations ///
int lfs_fs_traverse(lfs_t *lfs,
int (*cb)(void *data, lfs_block_t block), void *data) {
// iterate over metadata pairs
lfs_mdir_t dir = {.tail = {0, 1}};
while (!lfs_pair_isnull(dir.tail)) {
for (int i = 0; i < 2; i++) {
int err = cb(data, dir.tail[i]);
if (err) {
return err;
}
}
// iterate through ids in directory
int err = lfs_dir_fetch(lfs, &dir, dir.tail);
if (err) {
return err;
}
for (uint16_t id = 0; id < dir.count; id++) {
struct lfs_ctz ctz;
lfs_stag_t tag = lfs_dir_get(lfs, &dir, 0x7c3fe000,
LFS_MKTAG(LFS_TYPE_STRUCT, id, sizeof(ctz)), &ctz);
if (tag < 0) {
if (tag == LFS_ERR_NOENT) {
continue;
}
return tag;
}
lfs_ctz_fromle32(&ctz);
if (lfs_tag_type(tag) == LFS_TYPE_CTZSTRUCT) {
err = lfs_ctz_traverse(lfs, NULL, &lfs->rcache,
ctz.head, ctz.size, cb, data);
if (err) {
return err;
}
}
}
}
// iterate over any open files
for (lfs_file_t *f = (lfs_file_t*)lfs->mlist; f; f = f->next) {
if (f->type != LFS_TYPE_REG) {
continue;
}
if ((f->flags & LFS_F_DIRTY) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
f->ctz.head, f->ctz.size, cb, data);
if (err) {
return err;
}
}
if ((f->flags & LFS_F_WRITING) && !(f->flags & LFS_F_INLINE)) {
int err = lfs_ctz_traverse(lfs, &f->cache, &lfs->rcache,
f->block, f->pos, cb, data);
if (err) {
return err;
}
}
}
return 0;
}
static int lfs_fs_pred(lfs_t *lfs,
const lfs_block_t pair[2], lfs_mdir_t *pdir) {
// iterate over all directory directory entries
pdir->tail[0] = 0;
pdir->tail[1] = 1;
while (!lfs_pair_isnull(pdir->tail)) {
if (lfs_pair_cmp(pdir->tail, pair) == 0) {
return 0;
}
int err = lfs_dir_fetch(lfs, pdir, pdir->tail);
if (err) {
return err;
}
}
return LFS_ERR_NOENT;
}
struct lfs_fs_parent_match {
lfs_t *lfs;
const lfs_block_t pair[2];
};
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) ? tag : 0;
}
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;
while (!lfs_pair_isnull(parent->tail)) {
lfs_stag_t tag = lfs_dir_fetchmatch(lfs, parent, parent->tail,
0x7fc01fff, LFS_MKTAG(LFS_TYPE_DIRSTRUCT, 0, 8),
lfs_fs_parent_match, &(struct lfs_fs_parent_match){
lfs, {pair[0], pair[1]}});
if (tag) {
return tag;
}
}
return LFS_ERR_NOENT;
}
static int lfs_fs_relocate(lfs_t *lfs,
const lfs_block_t oldpair[2], lfs_block_t newpair[2]) {
// update internal root
if (lfs_pair_cmp(oldpair, lfs->root) == 0) {
LFS_DEBUG("Relocating root %"PRIu32" %"PRIu32,
newpair[0], newpair[1]);
lfs->root[0] = newpair[0];
lfs->root[1] = newpair[1];
}
// update internally tracked dirs
for (struct lfs_mlist *d = lfs->mlist; d; d = d->next) {
if (lfs_pair_cmp(oldpair, d->m.pair) == 0) {
d->m.pair[0] = newpair[0];
d->m.pair[1] = newpair[1];
}
}
// find parent
lfs_mdir_t parent;
lfs_stag_t tag = lfs_fs_parent(lfs, oldpair, &parent);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
if (tag != LFS_ERR_NOENT) {
// update disk, this creates a desync
lfs_global_orphans(lfs, +1);
lfs_pair_tole32(newpair);
int err = lfs_dir_commit(lfs, &parent,
&(struct lfs_mattr){.tag=tag, .buffer=newpair});
lfs_pair_fromle32(newpair);
if (err) {
return err;
}
// next step, clean up orphans
lfs_global_orphans(lfs, -1);
}
// find pred
int err = lfs_fs_pred(lfs, oldpair, &parent);
if (err && err != LFS_ERR_NOENT) {
return err;
}
// if we can't find dir, it must be new
if (err != LFS_ERR_NOENT) {
// replace bad pair, either we clean up desync, or no desync occured
parent.tail[0] = newpair[0];
parent.tail[1] = newpair[1];
err = lfs_dir_commit(lfs, &parent,
LFS_MKATTR(LFS_TYPE_TAIL + parent.split,
0x1ff, parent.tail, sizeof(parent.tail),
NULL));
if (err) {
return err;
}
}
return 0;
}
static int lfs_fs_demove(lfs_t *lfs) {
if (!lfs->globals.hasmove) {
return 0;
}
// Fix bad moves
LFS_DEBUG("Fixing move %"PRIu32" %"PRIu32" %"PRIu32,
lfs->globals.pair[0], lfs->globals.pair[1], lfs->globals.id);
// fetch and delete the moved entry
lfs_mdir_t movedir;
int err = lfs_dir_fetch(lfs, &movedir, lfs->globals.pair);
if (err) {
return err;
}
// rely on cancel logic inside commit
err = lfs_dir_commit(lfs, &movedir, NULL);
if (err) {
return err;
}
return 0;
}
static int lfs_fs_deorphan(lfs_t *lfs) {
if (!lfs->globals.orphans) {
return 0;
}
// Fix any orphans
lfs_mdir_t pdir = {.split = true};
lfs_mdir_t dir = {.tail = {0, 1}};
// iterate over all directory directory entries
while (!lfs_pair_isnull(dir.tail)) {
int err = lfs_dir_fetch(lfs, &dir, dir.tail);
if (err) {
return err;
}
// check head blocks for orphans
if (!pdir.split) {
// check if we have a parent
lfs_mdir_t parent;
lfs_stag_t tag = lfs_fs_parent(lfs, pdir.tail, &parent);
if (tag < 0 && tag != LFS_ERR_NOENT) {
return tag;
}
if (tag == LFS_ERR_NOENT) {
// we are an orphan
LFS_DEBUG("Fixing orphan %"PRIu32" %"PRIu32,
pdir.tail[0], pdir.tail[1]);
err = lfs_dir_drop(lfs, &pdir, &dir);
if (err) {
return err;
}
break;
}
lfs_block_t pair[2];
lfs_stag_t res = lfs_dir_get(lfs, &parent, 0x7fffe000, tag, pair);
if (res < 0) {
return res;
}
lfs_pair_fromle32(pair);
if (!lfs_pair_sync(pair, pdir.tail)) {
// we have desynced
LFS_DEBUG("Fixing half-orphan %"PRIu32" %"PRIu32,
pair[0], pair[1]);
pdir.tail[0] = pair[0];
pdir.tail[1] = pair[1];
err = lfs_dir_commit(lfs, &pdir,
LFS_MKATTR(LFS_TYPE_SOFTTAIL,
0x1ff, pdir.tail, sizeof(pdir.tail),
NULL));
if (err) {
return err;
}
break;
}
}
memcpy(&pdir, &dir, sizeof(pdir));
}
// mark orphans as fixed
lfs_global_orphans(lfs, -lfs->globals.orphans);
return 0;
}
static int lfs_fs_forceconsistency(lfs_t *lfs) {
int err = lfs_fs_demove(lfs);
if (err) {
return err;
}
err = lfs_fs_deorphan(lfs);
if (err) {
return err;
}
return 0;
}
static int lfs_fs_size_count(void *p, lfs_block_t block) {
(void)block;
lfs_size_t *size = p;
*size += 1;
return 0;
}
lfs_ssize_t lfs_fs_size(lfs_t *lfs) {
lfs_size_t size = 0;
int err = lfs_fs_traverse(lfs, lfs_fs_size_count, &size);
if (err) {
return err;
}
return size;
}
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