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lfs: use meaningful names for magic block identifiers

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The difference between 0xffffffff and 0xfffffffe is too subtle.  Use
names that reflect what the value represents.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>
This commit is contained in:
Peter A. Bigot
2019-08-03 09:17:47 -05:00
parent db054684a6
commit dc031ce1d9
1 changed files with 44 additions and 42 deletions
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lfs.c
+44 -42
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@@ -7,19 +7,21 @@
#include "lfs.h" #include "lfs.h"
#include "lfs_util.h" #include "lfs_util.h"
#define LFS_BLOCK_NULL ((lfs_block_t)-1)
#define LFS_BLOCK_INLINE ((lfs_block_t)-2)
/// Caching block device operations /// /// Caching block device operations ///
static inline void lfs_cache_drop(lfs_t *lfs, lfs_cache_t *rcache) { 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 // do not zero, cheaper if cache is readonly or only going to be
// written with identical data (during relocates) // written with identical data (during relocates)
(void)lfs; (void)lfs;
rcache->block = 0xffffffff; rcache->block = LFS_BLOCK_NULL;
} }
static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) { static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
// zero to avoid information leak // zero to avoid information leak
memset(pcache->buffer, 0xff, lfs->cfg->cache_size); memset(pcache->buffer, 0xff, lfs->cfg->cache_size);
pcache->block = 0xffffffff; pcache->block = LFS_BLOCK_NULL;
} }
static int lfs_bd_read(lfs_t *lfs, static int lfs_bd_read(lfs_t *lfs,
@@ -27,7 +29,7 @@ static int lfs_bd_read(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_block_t block, lfs_off_t off,
void *buffer, lfs_size_t size) { void *buffer, lfs_size_t size) {
uint8_t *data = buffer; uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff); LFS_ASSERT(block != LFS_BLOCK_NULL);
if (off+size > lfs->cfg->block_size) { if (off+size > lfs->cfg->block_size) {
return LFS_ERR_CORRUPT; return LFS_ERR_CORRUPT;
} }
@@ -121,7 +123,7 @@ static int lfs_bd_cmp(lfs_t *lfs,
static int lfs_bd_flush(lfs_t *lfs, static int lfs_bd_flush(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) { lfs_cache_t *pcache, lfs_cache_t *rcache, bool validate) {
if (pcache->block != 0xffffffff && pcache->block != 0xfffffffe) { if (pcache->block != LFS_BLOCK_NULL && pcache->block != LFS_BLOCK_INLINE) {
LFS_ASSERT(pcache->block < lfs->cfg->block_count); LFS_ASSERT(pcache->block < lfs->cfg->block_count);
lfs_size_t diff = lfs_alignup(pcache->size, lfs->cfg->prog_size); lfs_size_t diff = lfs_alignup(pcache->size, lfs->cfg->prog_size);
int err = lfs->cfg->prog(lfs->cfg, pcache->block, int err = lfs->cfg->prog(lfs->cfg, pcache->block,
@@ -171,7 +173,7 @@ static int lfs_bd_prog(lfs_t *lfs,
lfs_block_t block, lfs_off_t off, lfs_block_t block, lfs_off_t off,
const void *buffer, lfs_size_t size) { const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer; const uint8_t *data = buffer;
LFS_ASSERT(block != 0xffffffff); LFS_ASSERT(block != LFS_BLOCK_NULL);
LFS_ASSERT(off + size <= lfs->cfg->block_size); LFS_ASSERT(off + size <= lfs->cfg->block_size);
while (size > 0) { while (size > 0) {
@@ -201,7 +203,7 @@ static int lfs_bd_prog(lfs_t *lfs,
// pcache must have been flushed, either by programming and // pcache must have been flushed, either by programming and
// entire block or manually flushing the pcache // entire block or manually flushing the pcache
LFS_ASSERT(pcache->block == 0xffffffff); LFS_ASSERT(pcache->block == LFS_BLOCK_NULL);
// prepare pcache, first condition can no longer fail // prepare pcache, first condition can no longer fail
pcache->block = block; pcache->block = block;
@@ -229,7 +231,7 @@ static inline void lfs_pair_swap(lfs_block_t pair[2]) {
} }
static inline bool lfs_pair_isnull(const lfs_block_t pair[2]) { static inline bool lfs_pair_isnull(const lfs_block_t pair[2]) {
return pair[0] == 0xffffffff || pair[1] == 0xffffffff; return pair[0] == LFS_BLOCK_NULL || pair[1] == LFS_BLOCK_NULL;
} }
static inline int lfs_pair_cmp( static inline int lfs_pair_cmp(
@@ -571,7 +573,7 @@ static int lfs_dir_getread(lfs_t *lfs, const lfs_mdir_t *dir,
while (size > 0) { while (size > 0) {
lfs_size_t diff = size; lfs_size_t diff = size;
if (pcache && pcache->block == 0xfffffffe && if (pcache && pcache->block == LFS_BLOCK_INLINE &&
off < pcache->off + pcache->size) { off < pcache->off + pcache->size) {
if (off >= pcache->off) { if (off >= pcache->off) {
// is already in pcache? // is already in pcache?
@@ -588,7 +590,7 @@ static int lfs_dir_getread(lfs_t *lfs, const lfs_mdir_t *dir,
diff = lfs_min(diff, pcache->off-off); diff = lfs_min(diff, pcache->off-off);
} }
if (rcache->block == 0xfffffffe && if (rcache->block == LFS_BLOCK_INLINE &&
off < rcache->off + rcache->size) { off < rcache->off + rcache->size) {
if (off >= rcache->off) { if (off >= rcache->off) {
// is already in rcache? // is already in rcache?
@@ -606,7 +608,7 @@ static int lfs_dir_getread(lfs_t *lfs, const lfs_mdir_t *dir,
} }
// load to cache, first condition can no longer fail // load to cache, first condition can no longer fail
rcache->block = 0xfffffffe; rcache->block = LFS_BLOCK_INLINE;
rcache->off = lfs_aligndown(off, lfs->cfg->read_size); rcache->off = lfs_aligndown(off, lfs->cfg->read_size);
rcache->size = lfs_min(lfs_alignup(off+hint, lfs->cfg->read_size), rcache->size = lfs_min(lfs_alignup(off+hint, lfs->cfg->read_size),
lfs->cfg->cache_size); lfs->cfg->cache_size);
@@ -723,7 +725,7 @@ static int lfs_dir_traverse(lfs_t *lfs,
uint16_t fromid = lfs_tag_size(tag); uint16_t fromid = lfs_tag_size(tag);
uint16_t toid = lfs_tag_id(tag); uint16_t toid = lfs_tag_id(tag);
int err = lfs_dir_traverse(lfs, int err = lfs_dir_traverse(lfs,
buffer, 0, 0xffffffff, NULL, 0, true, buffer, 0, LFS_BLOCK_NULL, NULL, 0, true,
LFS_MKTAG(0x600, 0x3ff, 0), LFS_MKTAG(0x600, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_STRUCT, 0, 0), LFS_MKTAG(LFS_TYPE_STRUCT, 0, 0),
fromid, fromid+1, toid-fromid+diff, fromid, fromid+1, toid-fromid+diff,
@@ -783,15 +785,15 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
// now scan tags to fetch the actual dir and find possible match // now scan tags to fetch the actual dir and find possible match
for (int i = 0; i < 2; i++) { for (int i = 0; i < 2; i++) {
lfs_off_t off = 0; lfs_off_t off = 0;
lfs_tag_t ptag = 0xffffffff; lfs_tag_t ptag = LFS_BLOCK_NULL;
uint16_t tempcount = 0; uint16_t tempcount = 0;
lfs_block_t temptail[2] = {0xffffffff, 0xffffffff}; lfs_block_t temptail[2] = {LFS_BLOCK_NULL, LFS_BLOCK_NULL};
bool tempsplit = false; bool tempsplit = false;
lfs_stag_t tempbesttag = besttag; lfs_stag_t tempbesttag = besttag;
dir->rev = lfs_tole32(dir->rev); dir->rev = lfs_tole32(dir->rev);
uint32_t crc = lfs_crc(0xffffffff, &dir->rev, sizeof(dir->rev)); uint32_t crc = lfs_crc(LFS_BLOCK_NULL, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev); dir->rev = lfs_fromle32(dir->rev);
while (true) { while (true) {
@@ -860,7 +862,7 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
dir->split = tempsplit; dir->split = tempsplit;
// reset crc // reset crc
crc = 0xffffffff; crc = LFS_BLOCK_NULL;
continue; continue;
} }
@@ -1248,7 +1250,7 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
} }
// read erased state from next program unit // read erased state from next program unit
lfs_tag_t tag = 0xffffffff; lfs_tag_t tag = LFS_BLOCK_NULL;
int err = lfs_bd_read(lfs, int err = lfs_bd_read(lfs,
NULL, &lfs->rcache, sizeof(tag), NULL, &lfs->rcache, sizeof(tag),
commit->block, noff, &tag, sizeof(tag)); commit->block, noff, &tag, sizeof(tag));
@@ -1274,7 +1276,7 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
commit->off += sizeof(tag)+lfs_tag_size(tag); commit->off += sizeof(tag)+lfs_tag_size(tag);
commit->ptag = tag ^ (reset << 31); commit->ptag = tag ^ (reset << 31);
commit->crc = 0xffffffff; // reset crc for next "commit" commit->crc = LFS_BLOCK_NULL; // reset crc for next "commit"
} }
// flush buffers // flush buffers
@@ -1287,7 +1289,7 @@ static int lfs_dir_commitcrc(lfs_t *lfs, struct lfs_commit *commit) {
lfs_off_t off = commit->begin; lfs_off_t off = commit->begin;
lfs_off_t noff = off1; lfs_off_t noff = off1;
while (off < end) { while (off < end) {
uint32_t crc = 0xffffffff; uint32_t crc = LFS_BLOCK_NULL;
for (lfs_off_t i = off; i < noff+sizeof(uint32_t); i++) { for (lfs_off_t i = off; i < noff+sizeof(uint32_t); i++) {
// leave it up to caching to make this efficient // leave it up to caching to make this efficient
uint8_t dat; uint8_t dat;
@@ -1341,10 +1343,10 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_mdir_t *dir) {
// set defaults // set defaults
dir->off = sizeof(dir->rev); dir->off = sizeof(dir->rev);
dir->etag = 0xffffffff; dir->etag = LFS_BLOCK_NULL;
dir->count = 0; dir->count = 0;
dir->tail[0] = 0xffffffff; dir->tail[0] = LFS_BLOCK_NULL;
dir->tail[1] = 0xffffffff; dir->tail[1] = LFS_BLOCK_NULL;
dir->erased = false; dir->erased = false;
dir->split = false; dir->split = false;
@@ -1434,7 +1436,7 @@ static int lfs_dir_compact(lfs_t *lfs,
// find size // find size
lfs_size_t size = 0; lfs_size_t size = 0;
int err = lfs_dir_traverse(lfs, int err = lfs_dir_traverse(lfs,
source, 0, 0xffffffff, attrs, attrcount, false, source, 0, LFS_BLOCK_NULL, attrs, attrcount, false,
LFS_MKTAG(0x400, 0x3ff, 0), LFS_MKTAG(0x400, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_NAME, 0, 0), LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
begin, end, -begin, begin, end, -begin,
@@ -1526,8 +1528,8 @@ static int lfs_dir_compact(lfs_t *lfs,
struct lfs_commit commit = { struct lfs_commit commit = {
.block = dir->pair[1], .block = dir->pair[1],
.off = 0, .off = 0,
.ptag = 0xffffffff, .ptag = LFS_BLOCK_NULL,
.crc = 0xffffffff, .crc = LFS_BLOCK_NULL,
.begin = 0, .begin = 0,
.end = lfs->cfg->block_size - 8, .end = lfs->cfg->block_size - 8,
@@ -1556,7 +1558,7 @@ static int lfs_dir_compact(lfs_t *lfs,
// traverse the directory, this time writing out all unique tags // traverse the directory, this time writing out all unique tags
err = lfs_dir_traverse(lfs, err = lfs_dir_traverse(lfs,
source, 0, 0xffffffff, attrs, attrcount, false, source, 0, LFS_BLOCK_NULL, attrs, attrcount, false,
LFS_MKTAG(0x400, 0x3ff, 0), LFS_MKTAG(0x400, 0x3ff, 0),
LFS_MKTAG(LFS_TYPE_NAME, 0, 0), LFS_MKTAG(LFS_TYPE_NAME, 0, 0),
begin, end, -begin, begin, end, -begin,
@@ -1682,8 +1684,8 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
} }
// calculate changes to the directory // calculate changes to the directory
lfs_tag_t deletetag = 0xffffffff; lfs_tag_t deletetag = LFS_BLOCK_NULL;
lfs_tag_t createtag = 0xffffffff; lfs_tag_t createtag = LFS_BLOCK_NULL;
for (int i = 0; i < attrcount; i++) { for (int i = 0; i < attrcount; i++) {
if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_CREATE) { if (lfs_tag_type3(attrs[i].tag) == LFS_TYPE_CREATE) {
createtag = attrs[i].tag; createtag = attrs[i].tag;
@@ -1729,7 +1731,7 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_mdir_t *dir,
.block = dir->pair[0], .block = dir->pair[0],
.off = dir->off, .off = dir->off,
.ptag = dir->etag, .ptag = dir->etag,
.crc = 0xffffffff, .crc = LFS_BLOCK_NULL,
.begin = dir->off, .begin = dir->off,
.end = lfs->cfg->block_size - 8, .end = lfs->cfg->block_size - 8,
@@ -1813,8 +1815,8 @@ compact:
if (lfs_pair_cmp(d->m.pair, copy.pair) == 0) { if (lfs_pair_cmp(d->m.pair, copy.pair) == 0) {
d->m = *dir; d->m = *dir;
if (d->id == lfs_tag_id(deletetag)) { if (d->id == lfs_tag_id(deletetag)) {
d->m.pair[0] = 0xffffffff; d->m.pair[0] = LFS_BLOCK_NULL;
d->m.pair[1] = 0xffffffff; d->m.pair[1] = LFS_BLOCK_NULL;
} else if (d->id > lfs_tag_id(deletetag)) { } else if (d->id > lfs_tag_id(deletetag)) {
d->id -= 1; d->id -= 1;
if (d->type == LFS_TYPE_DIR) { if (d->type == LFS_TYPE_DIR) {
@@ -2129,7 +2131,7 @@ static int lfs_ctz_find(lfs_t *lfs,
lfs_block_t head, lfs_size_t size, lfs_block_t head, lfs_size_t size,
lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) { lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
if (size == 0) { if (size == 0) {
*block = 0xffffffff; *block = LFS_BLOCK_NULL;
*off = 0; *off = 0;
return 0; return 0;
} }
@@ -2426,7 +2428,7 @@ int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
if (lfs_tag_type3(tag) == LFS_TYPE_INLINESTRUCT) { if (lfs_tag_type3(tag) == LFS_TYPE_INLINESTRUCT) {
// load inline files // load inline files
file->ctz.head = 0xfffffffe; file->ctz.head = LFS_BLOCK_INLINE;
file->ctz.size = lfs_tag_size(tag); file->ctz.size = lfs_tag_size(tag);
file->flags |= LFS_F_INLINE; file->flags |= LFS_F_INLINE;
file->cache.block = file->ctz.head; file->cache.block = file->ctz.head;
@@ -2614,7 +2616,7 @@ static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
} }
// keep our reference to the rcache in sync // keep our reference to the rcache in sync
if (lfs->rcache.block != 0xffffffff) { if (lfs->rcache.block != LFS_BLOCK_NULL) {
lfs_cache_drop(lfs, &orig.cache); lfs_cache_drop(lfs, &orig.cache);
lfs_cache_drop(lfs, &lfs->rcache); lfs_cache_drop(lfs, &lfs->rcache);
} }
@@ -2762,7 +2764,7 @@ lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
return err; return err;
} }
} else { } else {
file->block = 0xfffffffe; file->block = LFS_BLOCK_INLINE;
file->off = file->pos; file->off = file->pos;
} }
@@ -2888,7 +2890,7 @@ lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
return err; return err;
} }
} else { } else {
file->block = 0xfffffffe; file->block = LFS_BLOCK_INLINE;
file->off = file->pos; file->off = file->pos;
} }
@@ -3374,7 +3376,7 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->cache_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 // 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_ASSERT(4*lfs_npw2(LFS_BLOCK_NULL / (lfs->cfg->block_size-2*4))
<= lfs->cfg->block_size); <= lfs->cfg->block_size);
// block_cycles = 0 is no longer supported. // block_cycles = 0 is no longer supported.
@@ -3446,8 +3448,8 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
} }
// setup default state // setup default state
lfs->root[0] = 0xffffffff; lfs->root[0] = LFS_BLOCK_NULL;
lfs->root[1] = 0xffffffff; lfs->root[1] = LFS_BLOCK_NULL;
lfs->mlist = NULL; lfs->mlist = NULL;
lfs->seed = 0; lfs->seed = 0;
lfs->gstate = (struct lfs_gstate){0}; lfs->gstate = (struct lfs_gstate){0};
@@ -4250,7 +4252,7 @@ static int lfs1_dir_fetch(lfs_t *lfs,
continue; continue;
} }
uint32_t crc = 0xffffffff; uint32_t crc = LFS_BLOCK_NULL;
lfs1_dir_tole32(&test); lfs1_dir_tole32(&test);
lfs1_crc(&crc, &test, sizeof(test)); lfs1_crc(&crc, &test, sizeof(test));
lfs1_dir_fromle32(&test); lfs1_dir_fromle32(&test);
@@ -4435,8 +4437,8 @@ static int lfs1_mount(lfs_t *lfs, struct lfs1 *lfs1,
} }
lfs->lfs1 = lfs1; lfs->lfs1 = lfs1;
lfs->lfs1->root[0] = 0xffffffff; lfs->lfs1->root[0] = LFS_BLOCK_NULL;
lfs->lfs1->root[1] = 0xffffffff; lfs->lfs1->root[1] = LFS_BLOCK_NULL;
// setup free lookahead // setup free lookahead
lfs->free.off = 0; lfs->free.off = 0;
@@ -4685,7 +4687,7 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
dir2.pair[1] = dir1.pair[1]; dir2.pair[1] = dir1.pair[1];
dir2.rev = dir1.d.rev; dir2.rev = dir1.d.rev;
dir2.off = sizeof(dir2.rev); dir2.off = sizeof(dir2.rev);
dir2.etag = 0xffffffff; dir2.etag = LFS_BLOCK_NULL;
dir2.count = 0; dir2.count = 0;
dir2.tail[0] = lfs->lfs1->root[0]; dir2.tail[0] = lfs->lfs1->root[0];
dir2.tail[1] = lfs->lfs1->root[1]; dir2.tail[1] = lfs->lfs1->root[1];