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Added lfs_rbyd_get, bumped hint back up to full during lookup

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The idea behind the full hint is that we may stay on the current search
path, benefiting from a loaded cache. Though this should probably be
benchmarked eventually.
This commit is contained in:
Christopher Haster
2022-12-28 15:45:48 -06:00
parent 3c17c94b94
commit 6c66e20349
2 changed files with 175 additions and 2 deletions
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lfs.c
+30 -2
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@@ -1172,7 +1172,7 @@ tryagain:;
lfs_rtag_t alt;
lfs_off_t jump;
lfs_ssize_t delta = lfs_rbyd_readtag(lfs,
&lfs->pcache, &lfs->rcache, 2*4,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
rbyd->block, branch, &alt, &jump, NULL);
if (delta < 0) {
return delta;
@@ -1216,6 +1216,34 @@ tryagain:;
}
}
static lfs_ssize_t lfs_rbyd_get(lfs_t *lfs, const lfs_rbyd_t *rbyd,
lfs_rtag_t tag, void *buffer, lfs_size_t size) {
lfs_off_t found_off;
lfs_size_t found_size;
lfs_srtag_t found_tag = lfs_rbyd_lookup(lfs, rbyd, tag,
&found_off, &found_size);
if (found_tag < 0) {
return found_tag;
}
// lookup finds the next-smallest tag, here we fail if it's not
// an exact match
if ((lfs_tag_t)found_tag != tag) {
return LFS_ERR_NOENT;
}
// note that it's highly likely the data is in our cache now
lfs_size_t delta = lfs_min(size, found_size);
int err = lfs_bd_read(lfs,
&lfs->pcache, &lfs->rcache, delta,
rbyd->block, found_off, buffer, delta);
if (err) {
return err;
}
return found_size;
}
static int lfs_rbyd_prog(lfs_t *lfs,
lfs_cache_t *pcache, lfs_cache_t *rcache,
lfs_block_t block, lfs_off_t off,
@@ -1438,7 +1466,7 @@ static int lfs_rbyd_commit(lfs_t *lfs, lfs_rbyd_t *rbyd,
lfs_rtag_t alt;
lfs_off_t jump;
lfs_ssize_t delta = lfs_rbyd_readtag(lfs,
&lfs->pcache, &lfs->rcache, 2*4,
&lfs->pcache, &lfs->rcache, lfs->cfg->block_size,
block, branch, &alt, &jump, NULL);
if (delta < 0) {
return delta;