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lfs.c
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lfs.c
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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->cache_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);
}
// 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;
}
enum {
LFS_CMP_EQ = 0,
LFS_CMP_LT = 1,
LFS_CMP_GT = 2,
};
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]) ? LFS_CMP_LT : LFS_CMP_GT;
}
}
return LFS_CMP_EQ;
}
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 < 0) {
return res;
}
if (res != LFS_CMP_EQ) {
return 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) << 20) | ((lfs_tag_t)(id) << 10) | (lfs_tag_t)(size))
static inline bool lfs_tag_isvalid(lfs_tag_t tag) {
return !(tag & 0x80000000);
}
static inline bool lfs_tag_isdelete(lfs_tag_t tag) {
return ((int32_t)(tag << 22) >> 22) == -1;
}
static inline uint16_t lfs_tag_type1(lfs_tag_t tag) {
return (tag & 0x70000000) >> 20;
}
static inline uint16_t lfs_tag_type3(lfs_tag_t tag) {
return (tag & 0x7ff00000) >> 20;
}
static inline uint8_t lfs_tag_chunk(lfs_tag_t tag) {
return (tag & 0x0ff00000) >> 20;
}
static inline int8_t lfs_tag_splice(lfs_tag_t tag) {
return (int8_t)lfs_tag_chunk(tag);
}
static inline uint16_t lfs_tag_id(lfs_tag_t tag) {
return (tag & 0x000ffc00) >> 10;
}
static inline lfs_size_t lfs_tag_size(lfs_tag_t tag) {
return tag & 0x000003ff;
}
static inline lfs_size_t lfs_tag_dsize(lfs_tag_t tag) {
return sizeof(tag) + lfs_tag_size(tag + lfs_tag_isdelete(tag));
}
// operations on attributes in attribute lists
struct lfs_mattr {
lfs_tag_t tag;
const void *buffer;
};
struct lfs_diskoff {
lfs_block_t block;
lfs_off_t off;
};
#define LFS_MKATTRS(...) \
(struct lfs_mattr[]){__VA_ARGS__}, \
sizeof((struct lfs_mattr[]){__VA_ARGS__}) / sizeof(struct lfs_mattr)
// operations on global state
static inline void lfs_gstate_xor(struct lfs_gstate *a,
const struct lfs_gstate *b) {
for (int i = 0; i < 3; i++) {
((uint32_t*)a)[i] ^= ((const uint32_t*)b)[i];
}
}
static inline bool lfs_gstate_iszero(const struct lfs_gstate *a) {
for (int i = 0; i < 3; i++) {
if (((uint32_t*)a)[i] != 0) {
return false;
}
}
return true;
}
static inline bool lfs_gstate_hasorphans(const struct lfs_gstate *a) {
return lfs_tag_size(a->tag);
}
static inline uint8_t lfs_gstate_getorphans(const struct lfs_gstate *a) {
return lfs_tag_size(a->tag);
}
static inline bool lfs_gstate_hasmove(const struct lfs_gstate *a) {
return lfs_tag_type1(a->tag);
}
static inline bool lfs_gstate_hasmovehere(const struct lfs_gstate *a,
const lfs_block_t *pair) {
return lfs_tag_type1(a->tag) && lfs_pair_cmp(a->pair, pair) == 0;
}
static inline void lfs_gstate_xororphans(struct lfs_gstate *a,
const struct lfs_gstate *b, bool orphans) {
a->tag ^= LFS_MKTAG(0x800, 0, 0) & (b->tag ^ (orphans << 31));
}
static inline void lfs_gstate_xormove(struct lfs_gstate *a,
const struct lfs_gstate *b, uint16_t id, const lfs_block_t pair[2]) {
a->tag ^= LFS_MKTAG(0x7ff, 0x3ff, 0) & (b->tag ^ (
(id != 0x3ff) ? LFS_MKTAG(LFS_TYPE_DELETE, id, 0) : 0));
a->pair[0] ^= b->pair[0] ^ ((id != 0x3ff) ? pair[0] : 0);
a->pair[1] ^= b->pair[1] ^ ((id != 0x3ff) ? pair[1] : 0);
}
static inline void lfs_gstate_fromle32(struct lfs_gstate *a) {
a->tag = lfs_fromle32(a->tag);
a->pair[0] = lfs_fromle32(a->pair[0]);
a->pair[1] = lfs_fromle32(a->pair[1]);
}
static inline void lfs_gstate_tole32(struct lfs_gstate *a) {
a->tag = lfs_tole32(a->tag);
a->pair[0] = lfs_tole32(a->pair[0]);
a->pair[1] = lfs_tole32(a->pair[1]);
}
// 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->file_max = lfs_fromle32(superblock->file_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->file_max = lfs_tole32(superblock->file_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, int attrcount);
static int lfs_dir_compact(lfs_t *lfs,
lfs_mdir_t *dir, const struct lfs_mattr *attrs, int attrcount,
lfs_mdir_t *source, uint16_t begin, uint16_t end);
static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file);
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file);
static void lfs_fs_preporphans(lfs_t *lfs, int8_t orphans);
static void lfs_fs_prepmove(lfs_t *lfs,
uint16_t id, const lfs_block_t pair[2]);
static int lfs_fs_pred(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *pdir);
static lfs_stag_t lfs_fs_parent(lfs_t *lfs, const lfs_block_t dir[2],
lfs_mdir_t *parent);
static int lfs_fs_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);
#ifdef LFS_MIGRATE
static int lfs1_traverse(lfs_t *lfs,
int (*cb)(void*, lfs_block_t), void *data);
#endif
/// 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 lfs_stag_t lfs_dir_getslice(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_tag_t gmask, lfs_tag_t gtag,
lfs_off_t goff, void *gbuffer, lfs_size_t gsize) {
lfs_off_t off = dir->off;
lfs_tag_t ntag = dir->etag;
lfs_stag_t gdiff = 0;
if (lfs_gstate_hasmovehere(&lfs->gstate, dir->pair) &&
lfs_tag_id(gtag) <= lfs_tag_id(lfs->gstate.tag)) {
// synthetic moves
gdiff -= LFS_MKTAG(0, 1, 0);
}
// iterate over dir block backwards (for faster lookups)
while (off >= sizeof(lfs_tag_t) + lfs_tag_dsize(ntag)) {
off -= lfs_tag_dsize(ntag);
lfs_tag_t tag = ntag;
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(ntag),
dir->pair[0], off, &ntag, sizeof(ntag));
if (err) {
return err;
}
ntag = (lfs_frombe32(ntag) ^ tag) & 0x7fffffff;
if (lfs_tag_id(gmask) != 0 &&
lfs_tag_type1(tag) == LFS_TYPE_SPLICE &&
lfs_tag_id(tag) <= lfs_tag_id(gtag - gdiff)) {
if (tag == (LFS_MKTAG(LFS_TYPE_CREATE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & (gtag - gdiff)))) {
// found where we were created
return LFS_ERR_NOENT;
}
// move around splices
gdiff += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
if ((gmask & tag) == (gmask & (gtag - gdiff))) {
if (lfs_tag_isdelete(tag)) {
return LFS_ERR_NOENT;
}
lfs_size_t diff = lfs_min(lfs_tag_size(tag), gsize);
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, diff,
dir->pair[0], off+sizeof(tag)+goff, gbuffer, diff);
if (err) {
return err;
}
memset((uint8_t*)gbuffer + diff, 0, gsize - diff);
return tag + gdiff;
}
}
return LFS_ERR_NOENT;
}
static lfs_stag_t lfs_dir_get(lfs_t *lfs, const lfs_mdir_t *dir,
lfs_tag_t gmask, lfs_tag_t gtag, void *buffer) {
return lfs_dir_getslice(lfs, dir,
gmask, gtag,
0, buffer, lfs_tag_size(gtag));
}
static int lfs_dir_getread(lfs_t *lfs, const lfs_mdir_t *dir,
const lfs_cache_t *pcache, lfs_cache_t *rcache, lfs_size_t hint,
lfs_tag_t gmask, lfs_tag_t gtag,
lfs_off_t off, void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
if (off+size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT;
}
while (size > 0) {
lfs_size_t diff = size;
if (pcache && pcache->block == 0xfffffffe &&
off < pcache->off + pcache->size) {
if (off >= pcache->off) {
// is already in pcache?
diff = lfs_min(diff, pcache->size - (off-pcache->off));
memcpy(data, &pcache->buffer[off-pcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// pcache takes priority
diff = lfs_min(diff, pcache->off-off);
}
if (rcache->block == 0xfffffffe &&
off < rcache->off + rcache->size) {
if (off >= rcache->off) {
// is already in rcache?
diff = lfs_min(diff, rcache->size - (off-rcache->off));
memcpy(data, &rcache->buffer[off-rcache->off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// rcache takes priority
diff = lfs_min(diff, rcache->off-off);
}
// load to cache, first condition can no longer fail
rcache->block = 0xfffffffe;
rcache->off = lfs_aligndown(off, lfs->cfg->read_size);
rcache->size = lfs_min(lfs_alignup(off+hint, lfs->cfg->read_size),
lfs->cfg->cache_size);
int err = lfs_dir_getslice(lfs, dir, gmask, gtag,
rcache->off, rcache->buffer, rcache->size);
if (err) {
return err;
}
}
return 0;
}
static int lfs_dir_traverse_filter(void *p,
lfs_tag_t tag, const void *buffer) {
lfs_tag_t *filtertag = p;
(void)buffer;
// check for redundancy
uint32_t mask = LFS_MKTAG(0x7ff, 0x3ff, 0);
if ((mask & tag) == (mask & *filtertag) ||
(mask & tag) == (LFS_MKTAG(LFS_TYPE_DELETE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & *filtertag))) {
return true;
}
// check if we need to adjust for created/deleted tags
if (lfs_tag_type1(tag) == LFS_TYPE_SPLICE &&
lfs_tag_id(tag) <= lfs_tag_id(*filtertag)) {
*filtertag += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
return false;
}
static int lfs_dir_traverse(lfs_t *lfs,
const lfs_mdir_t *dir, lfs_off_t off, lfs_tag_t ptag,
const struct lfs_mattr *attrs, int attrcount, bool hasseenmove,
lfs_tag_t tmask, lfs_tag_t ttag,
uint16_t begin, uint16_t end, int16_t diff,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
// iterate over directory and attrs
while (true) {
lfs_tag_t tag;
const void *buffer;
struct lfs_diskoff disk;
if (off+lfs_tag_dsize(ptag) < dir->off) {
off += lfs_tag_dsize(ptag);
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(tag),
dir->pair[0], off, &tag, sizeof(tag));
if (err) {
return err;
}
tag = (lfs_frombe32(tag) ^ ptag) | 0x80000000;
disk.block = dir->pair[0];
disk.off = off+sizeof(lfs_tag_t);
buffer = &disk;
ptag = tag;
} else if (attrcount > 0) {
tag = attrs[0].tag;
buffer = attrs[0].buffer;
attrs += 1;
attrcount -= 1;
} else if (!hasseenmove &&
lfs_gstate_hasmovehere(&lfs->gpending, dir->pair)) {
// Wait, we have pending move? Handle this here (we need to
// or else we risk letting moves fall out of date)
tag = lfs->gpending.tag & LFS_MKTAG(0x7ff, 0x3ff, 0);
buffer = NULL;
hasseenmove = true;
} else {
return 0;
}
lfs_tag_t mask = LFS_MKTAG(0x7ff, 0, 0);
if ((mask & tmask & tag) != (mask & tmask & ttag)) {
continue;
}
// do we need to filter? inlining the filtering logic here allows
// for some minor optimizations
if (lfs_tag_id(tmask) != 0) {
// scan for duplicates and update tag based on creates/deletes
int filter = lfs_dir_traverse(lfs,
dir, off, ptag, attrs, attrcount, hasseenmove,
0, 0, 0, 0, 0,
lfs_dir_traverse_filter, &tag);
if (filter < 0) {
return filter;
}
if (filter) {
continue;
}
// in filter range?
if (!(lfs_tag_id(tag) >= begin && lfs_tag_id(tag) < end)) {
continue;
}
}
// handle special cases for mcu-side operations
if (lfs_tag_type3(tag) == LFS_FROM_NOOP) {
// do nothing
} else if (lfs_tag_type3(tag) == LFS_FROM_MOVE) {
uint16_t fromid = lfs_tag_size(tag);
uint16_t toid = lfs_tag_id(tag);
int err = lfs_dir_traverse(lfs,
buffer, 0, 0xffffffff, NULL, 0, true,
LFS_MKTAG(0x600, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, 0, 0),
fromid, fromid+1, toid-fromid+diff,
cb, data);
if (err) {
return err;
}
} else if (lfs_tag_type3(tag) == LFS_FROM_USERATTRS) {
for (unsigned i = 0; i < lfs_tag_size(tag); i++) {
const struct lfs_attr *a = buffer;
int err = cb(data, LFS_MKTAG(LFS_TYPE_USERATTR + a[i].type,
lfs_tag_id(tag) + diff, a[i].size), a[i].buffer);
if (err) {
return err;
}
}
} else {
int err = cb(data, tag + LFS_MKTAG(0, diff, 0), buffer);
if (err) {
return err;
}
}
}
}
static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
lfs_mdir_t *dir, const lfs_block_t pair[2],
lfs_tag_t fmask, lfs_tag_t ftag, uint16_t *id,
int (*cb)(void *data, lfs_tag_t tag, const void *buffer), void *data) {
// we can find tag very efficiently during a fetch, since we're already
// scanning the entire directory
lfs_stag_t besttag = -1;
// find the block with the most recent revision
uint32_t revs[2] = {0, 0};
int r = 0;
for (int i = 0; i < 2; i++) {
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(revs[i]),
pair[i], 0, &revs[i], sizeof(revs[i]));
revs[i] = lfs_fromle32(revs[i]);
if (err && err != LFS_ERR_CORRUPT) {
return err;
}
if (err != LFS_ERR_CORRUPT &&
lfs_scmp(revs[i], revs[(i+1)%2]) > 0) {
r = i;
}
}
dir->pair[0] = pair[(r+0)%2];
dir->pair[1] = pair[(r+1)%2];
dir->rev = revs[(r+0)%2];
dir->off = 0; // nonzero = found some commits
// now scan tags to fetch the actual dir and find possible match
for (int i = 0; i < 2; i++) {
lfs_off_t off = 0;
lfs_tag_t ptag = 0xffffffff;
uint16_t tempcount = 0;
lfs_block_t temptail[2] = {0xffffffff, 0xffffffff};
bool tempsplit = false;
lfs_stag_t tempbesttag = besttag;
dir->rev = lfs_tole32(dir->rev);
uint32_t crc = lfs_crc(0xffffffff, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev);
while (true) {
// extract next tag
lfs_tag_t tag;
off += lfs_tag_dsize(ptag);
int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off, &tag, sizeof(tag));
if (err) {
if (err == LFS_ERR_CORRUPT) {
// can't continue?
dir->erased = false;
break;
}
return err;
}
crc = lfs_crc(crc, &tag, sizeof(tag));
tag = lfs_frombe32(tag) ^ ptag;
// next commit not yet programmed or we're not in valid range
if (!lfs_tag_isvalid(tag) ||
off + lfs_tag_dsize(tag) > lfs->cfg->block_size) {
dir->erased = (lfs_tag_type1(ptag) == LFS_TYPE_CRC &&
dir->off % lfs->cfg->prog_size == 0);
break;
}
ptag = tag;
if (lfs_tag_type1(tag) == LFS_TYPE_CRC) {
// check the crc attr
uint32_t dcrc;
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag), &dcrc, sizeof(dcrc));
if (err) {
if (err == LFS_ERR_CORRUPT) {
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
ptag ^= (lfs_tag_chunk(tag) & 1U) << 31;
// toss our crc into the filesystem seed for
// pseudorandom numbers
lfs->seed ^= crc;
// update with what's found so far
besttag = tempbesttag;
dir->off = off + lfs_tag_dsize(tag);
dir->etag = ptag;
dir->count = tempcount;
dir->tail[0] = temptail[0];
dir->tail[1] = temptail[1];
dir->split = tempsplit;
// reset crc
crc = 0xffffffff;
continue;
}
// crc the entry first, hopefully 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,
dir->pair[0], off+j, &dat, 1);
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return err;
}
crc = lfs_crc(crc, &dat, 1);
}
// directory modification tags?
if (lfs_tag_type1(tag) == LFS_TYPE_NAME) {
// increase count of files if necessary
if (lfs_tag_id(tag) >= tempcount) {
tempcount = lfs_tag_id(tag) + 1;
}
} else if (lfs_tag_type1(tag) == LFS_TYPE_SPLICE) {
tempcount += lfs_tag_splice(tag);
if (tag == (LFS_MKTAG(LFS_TYPE_DELETE, 0, 0) |
(LFS_MKTAG(0, 0x3ff, 0) & tempbesttag))) {
tempbesttag |= 0x80000000;
} else if (tempbesttag != -1 &&
lfs_tag_id(tag) <= lfs_tag_id(tempbesttag)) {
tempbesttag += LFS_MKTAG(0, lfs_tag_splice(tag), 0);
}
} else if (lfs_tag_type1(tag) == LFS_TYPE_TAIL) {
tempsplit = (lfs_tag_chunk(tag) & 1);
err = lfs_bd_read(lfs,
NULL, &lfs->rcache, lfs->cfg->block_size,
dir->pair[0], off+sizeof(tag), &temptail, 8);
if (err) {
if (err == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
}
lfs_pair_fromle32(temptail);
}
// found a match for our fetcher?
if ((fmask & tag) == (fmask & ftag)) {
int res = cb(data, tag, &(struct lfs_diskoff){
dir->pair[0], off+sizeof(tag)});
if (res < 0) {
if (res == LFS_ERR_CORRUPT) {
dir->erased = false;
break;
}
return res;
}
if (res == LFS_CMP_EQ) {
// found a match
tempbesttag = tag;
} else if (res == LFS_CMP_GT &&
lfs_tag_id(tag) <= lfs_tag_id(tempbesttag)) {
// found a greater match, keep track to keep things sorted
tempbesttag = tag | 0x80000000;
}
}
}
// consider what we have good enough
if (dir->off > 0) {
// synthetic move
if (lfs_gstate_hasmovehere(&lfs->gstate, dir->pair)) {
if (lfs_tag_id(lfs->gstate.tag) == lfs_tag_id(besttag)) {
besttag |= 0x80000000;
} else if (besttag != -1 &&
lfs_tag_id(lfs->gstate.tag) < lfs_tag_id(besttag)) {
besttag -= LFS_MKTAG(0, 1, 0);
}
}
// found tag? or found best id?
if (id) {
*id = lfs_min(lfs_tag_id(besttag), dir->count);
}
if (lfs_tag_isvalid(besttag)) {
return besttag;
} else if (lfs_tag_id(besttag) < dir->count) {
return LFS_ERR_NOENT;
} else {
return 0;
}
}
// failed, try the other block?
lfs_pair_swap(dir->pair);
dir->rev = revs[(r+1)%2];
}
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]) {
// note, mask=-1, tag=0 can never match a tag since this
// pattern has the invalid bit set
return lfs_dir_fetchmatch(lfs, dir, pair, -1, 0, NULL, NULL, NULL);
}
static int lfs_dir_getgstate(lfs_t *lfs, const lfs_mdir_t *dir,
struct lfs_gstate *gstate) {
struct lfs_gstate temp;
lfs_stag_t res = lfs_dir_get(lfs, dir, LFS_MKTAG(0x7ff, 0, 0),
LFS_MKTAG(LFS_TYPE_MOVESTATE, 0, sizeof(temp)), &temp);
if (res < 0 && res != LFS_ERR_NOENT) {
return res;
}
if (res != LFS_ERR_NOENT) {
// xor together to find resulting gstate
lfs_gstate_fromle32(&temp);
lfs_gstate_xor(gstate, &temp);
}
return 0;
}
static int lfs_dir_getinfo(lfs_t *lfs, lfs_mdir_t *dir,
uint16_t id, struct lfs_info *info) {
if (id == 0x3ff) {
// special case for root
strcpy(info->name, "/");
info->type = LFS_TYPE_DIR;