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[stat_cache] FAM: check hash collision before add

skip monitoring new entry if there is a hash collision in stat_cache
data structure associated with FAM
personal/stbuehler/ci-build
Glenn Strauss 3 years ago
parent
commit
18faa0910c
  1. 28
      src/stat_cache.c

28
src/stat_cache.c

@ -297,10 +297,17 @@ static void stat_cache_fam_dir_monitor(server *srv, stat_cache_fam *scf, stat_ca
/* is this directory already registered ? */
fam_dir_entry *fam_dir = scf->fam_dir;
if (NULL == fam_dir) {
fam_dir = fam_dir_entry_init();
/* already splayed scf->dir_ndx */
if (NULL != scf->dirs && scf->dirs->key == scf->dir_ndx) {
/* hash collision; preserve existing
* do not monitor new to avoid cache thrashing */
return;
} else {
fam_dir = fam_dir_entry_init();
scf->dirs = splaytree_insert(scf->dirs, scf->dir_ndx, fam_dir);
}
buffer_copy_string_len(fam_dir->name, name->ptr, scf->dirlen);
fam_dir->version = 1;
if (0 != FAMMonitorDirectory(&scf->fam, fam_dir->name->ptr,
@ -312,24 +319,9 @@ static void stat_cache_fam_dir_monitor(server *srv, stat_cache_fam *scf, stat_ca
"file:", name,
FamErrlist[FAMErrno]);
scf->dirs = splaytree_delete(scf->dirs, scf->dir_ndx);
fam_dir_entry_free(&scf->fam, fam_dir);
return;
} else {
int osize = splaytree_size(scf->dirs);
/* already splayed scf->dir_ndx */
if ((NULL != scf->dirs) && (scf->dirs->key == scf->dir_ndx)) {
/* hash collision: replace old entry */
fam_dir_entry_free(&scf->fam, scf->dirs->data);
scf->dirs->data = fam_dir;
} else {
scf->dirs = splaytree_insert(scf->dirs, scf->dir_ndx, fam_dir);
force_assert(osize == (splaytree_size(scf->dirs) - 1));
}
force_assert(scf->dirs);
force_assert(scf->dirs->data == fam_dir);
scf->fam_dir = fam_dir;
}
}

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