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Tweaked lfsr_remove/rename to use lfsr_mtree_seek for empty dir check

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Also a bit of reordering lets us avoid a second mdir allocation, since
we can store the dstart mid/rid in the grm immediately. It's stack
allocated so just gets dropped if our dir turns out to not be empty.

            code          stack
  before:  22654           2344
  after:   22586 (-0.3%)   2320 (-1.0%)
This commit is contained in:
Christopher Haster
2023-07-29 01:04:40 -05:00
parent 8499f4cfb2
commit ee9cc185a1
1 changed files with 42 additions and 59 deletions
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lfs.c
+42 -59
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@@ -7533,46 +7533,37 @@ int lfsr_remove(lfs_t *lfs, const char *path) {
return d;
}
// check that the directory is empty
lfsr_mdir_t dstart_mdir;
lfs_ssize_t dstart_rid;
// then lookup the dstart entry
lfsr_mdir_t mdir_;
lfs_ssize_t rid_;
err = lfsr_mtree_dnamelookup(lfs, did, NULL, 0,
&dstart_mdir, &dstart_rid, NULL, NULL);
&mdir_, &rid_, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
lfsr_mdir_t mdir_ = dstart_mdir;
lfs_ssize_t rid_ = dstart_rid + 1;
if (rid_ >= (lfs_ssize_t)mdir_.rbyd.weight) {
// out of mdirs?
lfs_ssize_t mid = mdir_.mid + 1;
if (mid >= (lfs_ssize_t)lfsr_mtree_weight(lfs)) {
goto empty;
}
// create a grm to remove the dstart entry
lfsr_grm_pushrm(&grm, mdir_.mid, rid_);
int err = lfsr_mtree_lookup(lfs, mid, &mdir_);
if (err) {
return err;
}
rid_ = 0;
}
lfsr_tag_t tag_;
err = lfsr_mdir_lookup(lfs, &mdir_, rid_, LFSR_TAG_WIDENAME,
&tag_, NULL);
if (err) {
// check that the directory is empty
err = lfsr_mtree_seek(lfs, &mdir_, &rid_, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (tag_ != LFSR_TAG_DSTART) {
return LFS_ERR_NOTEMPTY;
}
empty:;
if (err != LFS_ERR_NOENT) {
lfsr_tag_t tag_;
err = lfsr_mdir_lookup(lfs, &mdir_, rid_, LFSR_TAG_WIDENAME,
&tag_, NULL);
if (err) {
return err;
}
// create a grm to remove the dstart entry
lfsr_grm_pushrm(&grm, dstart_mdir.mid, dstart_rid);
if (tag_ != LFSR_TAG_DSTART) {
return LFS_ERR_NOTEMPTY;
}
}
// adjust rid if grm is on the same mdir as our dir
if (grm.rms[0].mid == mdir.mid
@@ -7657,9 +7648,10 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
}
// if our destination is a directory, we will be implicitly removing
// the directory, we need to great a grm for this
// the directory, we need to create a grm for this
if (new_tag == LFSR_TAG_DIR) {
// TODO deduplicate the isempty check with lfsr_remove?
// first lets figure out the did
lfsr_data_t data;
int err = lfsr_mdir_lookup(lfs, &new_mdir, new_rid, LFSR_TAG_DID,
NULL, &data);
@@ -7673,46 +7665,37 @@ int lfsr_rename(lfs_t *lfs, const char *old_path, const char *new_path) {
return d;
}
// check that the directory is empty
lfsr_mdir_t dstart_mdir;
lfs_ssize_t dstart_rid;
// then lookup the dstart entry
lfsr_mdir_t mdir_;
lfs_ssize_t rid_;
err = lfsr_mtree_dnamelookup(lfs, did, NULL, 0,
&dstart_mdir, &dstart_rid, NULL, NULL);
&mdir_, &rid_, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
lfsr_mdir_t mdir_ = dstart_mdir;
lfs_ssize_t rid_ = dstart_rid + 1;
if (rid_ >= (lfs_ssize_t)mdir_.rbyd.weight) {
// out of mdirs?
lfs_ssize_t mid = mdir_.mid + 1;
if (mid >= (lfs_ssize_t)lfsr_mtree_weight(lfs)) {
goto empty;
}
// create a grm to remove the dstart entry
lfsr_grm_pushrm(&grm, mdir_.mid, rid_);
int err = lfsr_mtree_lookup(lfs, mid, &mdir_);
if (err) {
return err;
}
rid_ = 0;
}
lfsr_tag_t tag_;
err = lfsr_mdir_lookup(lfs, &mdir_, rid_, LFSR_TAG_WIDENAME,
&tag_, NULL);
if (err) {
// check that the directory is empty
err = lfsr_mtree_seek(lfs, &mdir_, &rid_, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (tag_ != LFSR_TAG_DSTART) {
return LFS_ERR_NOTEMPTY;
}
empty:;
if (err != LFS_ERR_NOENT) {
lfsr_tag_t tag_;
err = lfsr_mdir_lookup(lfs, &mdir_, rid_, LFSR_TAG_WIDENAME,
&tag_, NULL);
if (err) {
return err;
}
// create a grm to remove the dstart entry
lfsr_grm_pushrm(&grm, dstart_mdir.mid, dstart_rid);
if (tag_ != LFSR_TAG_DSTART) {
return LFS_ERR_NOTEMPTY;
}
}
}
}