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Added conversion to/from little-endian on disk

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Required to support big-endian processors, with the most notable being
the PowerPC architecture.

On little-endian architectures, these conversions can be optimized out
and have no code impact.

Initial patch provided by gmouchard
This commit is contained in:
Christopher Haster
2018-02-03 23:04:53 -06:00
parent dbce53672b
commit ebc0d24211
2 changed files with 100 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

139
lfs.c
View File

@@ -21,37 +21,7 @@
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <sys/param.h>
#if (__GNUC__ >= 4) && (__GNUC_MINOR__ >= 3)
#define LFS_BSWAP32(v) __builtin_bswap32(v);
#else
#define LFS_BSWAP32(v) ((((uint32_t)(v) & 0xff000000) >> 24) | (((uint32_t)(v) & 0x00ff0000) >> 8) | (((uint32_t)(v) & 0x0000ff00) << 8) | (((uint32_t)(v) & 0x000000ff) << 24))
#endif
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define LFS_ENDIAN_CONV_U32(v) do { (v) = LFS_BSWAP32(v); } while(0)
#else
#define LFS_ENDIAN_CONV_U32(v)
#endif
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define LFS_ENDIAN_CONV_DISK_DIR(v) do { LFS_ENDIAN_CONV_U32(v.rev); LFS_ENDIAN_CONV_U32(v.size); LFS_ENDIAN_CONV_U32(v.tail[0]); LFS_ENDIAN_CONV_U32(v.tail[1]); } while(0)
#else
#define LFS_ENDIAN_CONV_DISK_DIR(v)
#endif
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define LFS_ENDIAN_CONV_DISK_ENTRY(v) do { LFS_ENDIAN_CONV_U32(v.u.dir[0]); LFS_ENDIAN_CONV_U32(v.u.dir[1]); } while(0)
#else
#define LFS_ENDIAN_CONV_DISK_ENTRY(v)
#endif
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
#define LFS_ENDIAN_CONV_DISK_SUPERBLOCK(v) do { LFS_ENDIAN_CONV_U32(v.root[0]); LFS_ENDIAN_CONV_U32(v.root[1]); LFS_ENDIAN_CONV_U32(v.block_size); LFS_ENDIAN_CONV_U32(v.block_count); LFS_ENDIAN_CONV_U32(v.version); } while(0)
#else
#define LFS_ENDIAN_CONV_DISK_SUPERBLOCK(v)
#endif
/// Caching block device operations ///
static int lfs_cache_read(lfs_t *lfs, lfs_cache_t *rcache,
@@ -356,6 +326,48 @@ static void lfs_alloc_ack(lfs_t *lfs) {
}
/// Endian swapping functions ///
static void lfs_dir_fromle32(struct lfs_disk_dir *d) {
d->rev = lfs_fromle32(d->rev);
d->size = lfs_fromle32(d->size);
d->tail[0] = lfs_fromle32(d->tail[0]);
d->tail[1] = lfs_fromle32(d->tail[1]);
}
static void lfs_dir_tole32(struct lfs_disk_dir *d) {
d->rev = lfs_tole32(d->rev);
d->size = lfs_tole32(d->size);
d->tail[0] = lfs_tole32(d->tail[0]);
d->tail[1] = lfs_tole32(d->tail[1]);
}
static void lfs_entry_fromle32(struct lfs_disk_entry *d) {
d->u.dir[0] = lfs_fromle32(d->u.dir[0]);
d->u.dir[1] = lfs_fromle32(d->u.dir[1]);
}
static void lfs_entry_tole32(struct lfs_disk_entry *d) {
d->u.dir[0] = lfs_tole32(d->u.dir[0]);
d->u.dir[1] = lfs_tole32(d->u.dir[1]);
}
static void lfs_superblock_fromle32(struct lfs_disk_superblock *d) {
d->root[0] = lfs_fromle32(d->root[0]);
d->root[1] = lfs_fromle32(d->root[1]);
d->block_size = lfs_fromle32(d->block_size);
d->block_count = lfs_fromle32(d->block_count);
d->version = lfs_fromle32(d->version);
}
static void lfs_superblock_tole32(struct lfs_disk_superblock *d) {
d->root[0] = lfs_tole32(d->root[0]);
d->root[1] = lfs_tole32(d->root[1]);
d->block_size = lfs_tole32(d->block_size);
d->block_count = lfs_tole32(d->block_count);
d->version = lfs_tole32(d->version);
}
/// Metadata pair and directory operations ///
static inline void lfs_pairswap(lfs_block_t pair[2]) {
lfs_block_t t = pair[0];
@@ -397,10 +409,10 @@ static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->d.rev, 4);
dir->d.rev = lfs_fromle32(dir->d.rev);
if (err) {
return err;
}
LFS_ENDIAN_CONV_U32(dir->d.rev); // little-endian to host conversion
// set defaults
dir->d.rev += 1;
@@ -423,10 +435,10 @@ static int lfs_dir_fetch(lfs_t *lfs,
for (int i = 0; i < 2; i++) {
struct lfs_disk_dir test;
int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
lfs_dir_fromle32(&test);
if (err) {
return err;
}
LFS_ENDIAN_CONV_DISK_DIR(test); // little-endian to host conversion
if (valid && lfs_scmp(test.rev, dir->d.rev) < 0) {
continue;
@@ -437,10 +449,10 @@ static int lfs_dir_fetch(lfs_t *lfs,
continue;
}
LFS_ENDIAN_CONV_DISK_DIR(test); // host to little-endian conversion
uint32_t crc = 0xffffffff;
lfs_dir_tole32(&test);
lfs_crc(&crc, &test, sizeof(test));
LFS_ENDIAN_CONV_DISK_DIR(test); // little-endian to host conversion
lfs_dir_fromle32(&test);
err = lfs_bd_crc(lfs, tpair[i], sizeof(test),
(0x7fffffff & test.size) - sizeof(test), &crc);
if (err) {
@@ -500,9 +512,10 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
}
uint32_t crc = 0xffffffff;
lfs_dir_t _dir; _dir.d = dir->d; LFS_ENDIAN_CONV_DISK_DIR(_dir.d); // host to little-endian conversion
lfs_crc(&crc, &_dir.d, sizeof(_dir.d));
err = lfs_bd_prog(lfs, dir->pair[0], 0, &_dir.d, sizeof(_dir.d));
lfs_dir_tole32(&dir->d);
lfs_crc(&crc, &dir->d, sizeof(dir->d));
err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
lfs_dir_fromle32(&dir->d);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
@@ -549,9 +562,9 @@ static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
}
}
LFS_ENDIAN_CONV_U32(crc); // host to little-endian conversion
crc = lfs_tole32(crc);
err = lfs_bd_prog(lfs, dir->pair[0], newoff, &crc, 4);
LFS_ENDIAN_CONV_U32(crc); // little-endian to host conversion
crc = lfs_fromle32(crc);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
@@ -624,12 +637,14 @@ relocate:
}
static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
const lfs_entry_t *entry, const void *data) {
lfs_entry_t _entry; _entry.d = entry->d; LFS_ENDIAN_CONV_DISK_ENTRY(_entry.d); // host to little-endian conversion
return lfs_dir_commit(lfs, dir, (struct lfs_region[]){
{entry->off, sizeof(entry->d), &_entry.d, sizeof(entry->d)},
lfs_entry_t *entry, const void *data) {
lfs_entry_tole32(&entry->d);
int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
{entry->off, sizeof(entry->d), &entry->d, sizeof(entry->d)},
{entry->off+sizeof(entry->d), entry->d.nlen, data, entry->d.nlen}
}, data ? 2 : 1);
lfs_entry_fromle32(&entry->d);
return err;
}
static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
@@ -638,11 +653,14 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
while (true) {
if (dir->d.size + lfs_entry_size(entry) <= lfs->cfg->block_size) {
entry->off = dir->d.size - 4;
lfs_entry_t _entry; _entry.d = entry->d; LFS_ENDIAN_CONV_DISK_ENTRY(_entry.d); // host to little-endian conversion
return lfs_dir_commit(lfs, dir, (struct lfs_region[]){
{entry->off, 0, &_entry.d, sizeof(entry->d)},
lfs_entry_tole32(&entry->d);
int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
{entry->off, 0, &entry->d, sizeof(entry->d)},
{entry->off, 0, data, entry->d.nlen}
}, 2);
lfs_entry_fromle32(&entry->d);
return err;
}
// we need to allocate a new dir block
@@ -656,11 +674,12 @@ static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
newdir.d.tail[0] = dir->d.tail[0];
newdir.d.tail[1] = dir->d.tail[1];
entry->off = newdir.d.size - 4;
lfs_entry_t _entry; _entry.d = entry->d; LFS_ENDIAN_CONV_DISK_ENTRY(_entry.d); // host to little-endian conversion
lfs_entry_tole32(&entry->d);
err = lfs_dir_commit(lfs, &newdir, (struct lfs_region[]){
{entry->off, 0, &_entry.d, sizeof(entry->d)},
{entry->off, 0, &entry->d, sizeof(entry->d)},
{entry->off, 0, data, entry->d.nlen}
}, 2);
lfs_entry_fromle32(&entry->d);
if (err) {
return err;
}
@@ -746,10 +765,10 @@ static int lfs_dir_next(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
int err = lfs_bd_read(lfs, dir->pair[0], dir->off,
&entry->d, sizeof(entry->d));
lfs_entry_fromle32(&entry->d);
if (err) {
return err;
}
LFS_ENDIAN_CONV_DISK_ENTRY(entry->d); // little-endian to host conversion
entry->off = dir->off;
dir->off += lfs_entry_size(entry);
@@ -1108,10 +1127,10 @@ static int lfs_ctz_find(lfs_t *lfs,
lfs_ctz(current));
int err = lfs_cache_read(lfs, rcache, pcache, head, 4*skip, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
LFS_ENDIAN_CONV_U32(head); // little-endian to host conversion
assert(head >= 2 && head <= lfs->cfg->block_count);
current -= 1 << skip;
@@ -1184,10 +1203,10 @@ static int lfs_ctz_extend(lfs_t *lfs,
lfs_size_t skips = lfs_ctz(index) + 1;
for (lfs_off_t i = 0; i < skips; i++) {
LFS_ENDIAN_CONV_U32(head); // host to little-endian conversion
head = lfs_tole32(head);
int err = lfs_cache_prog(lfs, pcache, rcache,
nblock, 4*i, &head, 4);
LFS_ENDIAN_CONV_U32(head); // little-endian to host conversion
head = lfs_fromle32(head);
if (err) {
if (err == LFS_ERR_CORRUPT) {
goto relocate;
@@ -1198,10 +1217,10 @@ static int lfs_ctz_extend(lfs_t *lfs,
if (i != skips-1) {
err = lfs_cache_read(lfs, rcache, NULL,
head, 4*i, &head, 4);
head = lfs_fromle32(head);
if (err) {
return err;
}
LFS_ENDIAN_CONV_U32(head); // little-endian to host conversion
}
assert(head >= 2 && head <= lfs->cfg->block_count);
@@ -1243,11 +1262,11 @@ static int lfs_ctz_traverse(lfs_t *lfs,
lfs_block_t heads[2];
int count = 2 - (index & 1);
err = lfs_cache_read(lfs, rcache, pcache, head, 0, &heads, count*4);
heads[0] = lfs_fromle32(heads[0]);
heads[1] = lfs_fromle32(heads[1]);
if (err) {
return err;
}
LFS_ENDIAN_CONV_U32(heads[0]); // host to little-endian conversion
LFS_ENDIAN_CONV_U32(heads[1]); // host to little-endian conversion
for (int i = 0; i < count-1; i++) {
err = cb(data, heads[i]);
@@ -1505,10 +1524,10 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
lfs_entry_t entry = {.off = file->poff};
err = lfs_bd_read(lfs, cwd.pair[0], entry.off,
&entry.d, sizeof(entry.d));
lfs_entry_fromle32(&entry.d);
if (err) {
return err;
}
LFS_ENDIAN_CONV_DISK_ENTRY(entry.d); // little-endian to host conversion
if (entry.d.type != LFS_TYPE_REG) {
// sanity check valid entry
@@ -2126,12 +2145,12 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
superdir.d.size = sizeof(superdir.d) + sizeof(superblock.d) + 4;
// write both pairs to be safe
lfs_superblock_tole32(&superblock.d);
bool valid = false;
for (int i = 0; i < 2; i++) {
lfs_superblock_t _superblock; _superblock.d = superblock.d; LFS_ENDIAN_CONV_DISK_SUPERBLOCK(_superblock.d); // host to little-endian conversion
int err = lfs_dir_commit(lfs, &superdir, (struct lfs_region[]){
{sizeof(superdir.d), sizeof(superblock.d),
&_superblock.d, sizeof(superblock.d)}
&superblock.d, sizeof(superblock.d)}
}, 1);
if (err && err != LFS_ERR_CORRUPT) {
return err;
@@ -2176,10 +2195,10 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
if (!err) {
int err = lfs_bd_read(lfs, dir.pair[0], sizeof(dir.d),
&superblock.d, sizeof(superblock.d));
lfs_superblock_fromle32(&superblock.d);
if (err) {
return err;
}
LFS_ENDIAN_CONV_DISK_SUPERBLOCK(superblock.d); // little-endian to host conversion
lfs->root[0] = superblock.d.root[0];
lfs->root[1] = superblock.d.root[1];
@@ -2233,10 +2252,10 @@ int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
while (dir.off + sizeof(entry.d) <= (0x7fffffff & dir.d.size)-4) {
int err = lfs_bd_read(lfs, dir.pair[0], dir.off,
&entry.d, sizeof(entry.d));
lfs_entry_fromle32(&entry.d);
if (err) {
return err;
}
LFS_ENDIAN_CONV_DISK_ENTRY(entry.d); // little-endian to host conversion
dir.off += lfs_entry_size(&entry);
if ((0x70 & entry.d.type) == (0x70 & LFS_TYPE_REG)) {

17
lfs_util.h
View File

@@ -49,6 +49,23 @@ static inline int lfs_scmp(uint32_t a, uint32_t b) {
return (int)(unsigned)(a - b);
}
static inline uint32_t lfs_fromle32(uint32_t a) {
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
return a;
#elif defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
return __builtin_bswap32(a);
#else
return (((uint8_t*)&a)[0] << 0) |
(((uint8_t*)&a)[1] << 8) |
(((uint8_t*)&a)[2] << 16) |
(((uint8_t*)&a)[3] << 24);
#endif
}
static inline uint32_t lfs_tole32(uint32_t a) {
return lfs_fromle32(a);
}
// CRC-32 with polynomial = 0x04c11db7
void lfs_crc(uint32_t *crc, const void *buffer, size_t size);