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Fixed problem with lookaheads larger than block device

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Simply limiting the lookahead region to the size of
the block device fixes the problem.

Also added logic to limit the allocated region and
floor to nearest word, since the additional memory
couldn't really be used effectively.
This commit is contained in:
Christopher Haster
2017-09-18 21:20:33 -05:00
parent d9367e05ce
commit 273cb7c9c8
3 changed files with 29 additions and 24 deletions
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45
lfs.c
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@@ -262,12 +262,12 @@ int lfs_deorphan(lfs_t *lfs);
static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
lfs_t *lfs = p;
lfs_block_t off = (((lfs_soff_t)(block - lfs->free.start)
lfs_block_t off = (((lfs_soff_t)(block - lfs->free.begin)
% (lfs_soff_t)(lfs->cfg->block_count))
+ lfs->cfg->block_count) % lfs->cfg->block_count;
if (off < lfs->cfg->lookahead) {
lfs->free.lookahead[off / 32] |= 1U << (off % 32);
if (off < lfs->free.lookahead) {
lfs->free.buffer[off / 32] |= 1U << (off % 32);
}
return 0;
@@ -285,30 +285,30 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
while (true) {
while (true) {
// check if we have looked at all blocks since last ack
if (lfs->free.start + lfs->free.off == lfs->free.end) {
if (lfs->free.begin + lfs->free.off == lfs->free.end) {
LFS_WARN("No more free space %d", lfs->free.end);
return LFS_ERR_NOSPC;
}
if (lfs->free.off >= lfs->cfg->lookahead) {
if (lfs->free.off >= lfs->free.lookahead) {
break;
}
lfs_block_t off = lfs->free.off;
lfs->free.off += 1;
if (!(lfs->free.lookahead[off / 32] & (1U << (off % 32)))) {
if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
// found a free block
*block = (lfs->free.start + off) % lfs->cfg->block_count;
*block = (lfs->free.begin + off) % lfs->cfg->block_count;
return 0;
}
}
lfs->free.start += lfs->cfg->lookahead;
lfs->free.begin += lfs->free.lookahead;
lfs->free.off = 0;
// find mask of free blocks from tree
memset(lfs->free.lookahead, 0, lfs->cfg->lookahead/8);
memset(lfs->free.buffer, 0, lfs->free.lookahead/8);
int err = lfs_traverse(lfs, lfs_alloc_lookahead, lfs);
if (err) {
return err;
@@ -317,7 +317,7 @@ static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
}
static void lfs_alloc_ack(lfs_t *lfs) {
lfs->free.end = lfs->free.start + lfs->free.off + lfs->cfg->block_count;
lfs->free.end = lfs->free.begin + lfs->free.off + lfs->cfg->block_count;
}
@@ -1786,12 +1786,15 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
}
}
// setup lookahead
// setup lookahead, round down to nearest 32-bits
lfs->free.lookahead = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
lfs->free.lookahead = 32 * (lfs->free.lookahead / 32);
assert(lfs->free.lookahead > 0);
if (lfs->cfg->lookahead_buffer) {
lfs->free.lookahead = lfs->cfg->lookahead_buffer;
lfs->free.buffer = lfs->cfg->lookahead_buffer;
} else {
lfs->free.lookahead = malloc(lfs->cfg->lookahead/8);
if (!lfs->free.lookahead) {
lfs->free.buffer = malloc(lfs->free.lookahead/8);
if (!lfs->free.buffer) {
return LFS_ERR_NOMEM;
}
}
@@ -1816,7 +1819,7 @@ static int lfs_deinit(lfs_t *lfs) {
}
if (!lfs->cfg->lookahead_buffer) {
free(lfs->free.lookahead);
free(lfs->free.buffer);
}
return 0;
@@ -1829,10 +1832,10 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
}
// create free lookahead
memset(lfs->free.lookahead, 0, lfs->cfg->lookahead/8);
lfs->free.start = 0;
memset(lfs->free.buffer, 0, lfs->free.lookahead/8);
lfs->free.begin = 0;
lfs->free.off = 0;
lfs->free.end = lfs->free.start + lfs->cfg->block_count;
lfs->free.end = lfs->free.begin + lfs->cfg->block_count;
// create superblock dir
lfs_alloc_ack(lfs);
@@ -1908,9 +1911,9 @@ int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
}
// setup free lookahead
lfs->free.start = -lfs->cfg->lookahead;
lfs->free.off = lfs->cfg->lookahead;
lfs->free.end = lfs->free.start + lfs->cfg->block_count;
lfs->free.begin = -lfs->free.lookahead;
lfs->free.off = lfs->free.lookahead;
lfs->free.end = lfs->free.begin + lfs->cfg->block_count;
// load superblock
lfs_dir_t dir;