From e0d7d0e45c5652bccc160ec49fc0c2c26d9c4d4e Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Fri, 1 Aug 2014 17:20:25 +0200 Subject: [PATCH] findRoots(): Prevent a call to lstat() This means that getting the roots from /nix/var/nix/.../hydra-roots doesn't need any I/O other than reading the directory. --- src/libstore/gc.cc | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc index df6f26c77..e5836150c 100644 --- a/src/libstore/gc.cc +++ b/src/libstore/gc.cc @@ -294,18 +294,23 @@ static void foundRoot(StoreAPI & store, } -static void findRoots(StoreAPI & store, const Path & path, Roots & roots) +static void findRoots(StoreAPI & store, const Path & path, unsigned char type, Roots & roots) { try { - struct stat st = lstat(path); - - if (S_ISDIR(st.st_mode)) { - for (auto & i : readDirectory(path)) - findRoots(store, path + "/" + i.name, roots); + if (type == DT_UNKNOWN) { + struct stat st = lstat(path); + if (S_ISDIR(st.st_mode)) type = DT_DIR; + else if (S_ISLNK(st.st_mode)) type = DT_LNK; + else if (S_ISREG(st.st_mode)) type = DT_REG; } - else if (S_ISLNK(st.st_mode)) { + if (type == DT_DIR) { + for (auto & i : readDirectory(path)) + findRoots(store, path + "/" + i.name, i.type, roots); + } + + else if (type == DT_LNK) { Path target = readLink(path); if (isInStore(target)) foundRoot(store, path, target, roots); @@ -327,7 +332,7 @@ static void findRoots(StoreAPI & store, const Path & path, Roots & roots) } } - else if (S_ISREG(st.st_mode)) { + else if (type == DT_REG) { Path storePath = settings.nixStore + "/" + baseNameOf(path); if (store.isValidPath(storePath)) roots[path] = storePath; @@ -350,9 +355,9 @@ Roots LocalStore::findRoots() Roots roots; /* Process direct roots in {gcroots,manifests,profiles}. */ - nix::findRoots(*this, settings.nixStateDir + "/" + gcRootsDir, roots); - nix::findRoots(*this, settings.nixStateDir + "/manifests", roots); - nix::findRoots(*this, settings.nixStateDir + "/profiles", roots); + nix::findRoots(*this, settings.nixStateDir + "/" + gcRootsDir, DT_UNKNOWN, roots); + nix::findRoots(*this, settings.nixStateDir + "/manifests", DT_UNKNOWN, roots); + nix::findRoots(*this, settings.nixStateDir + "/profiles", DT_UNKNOWN, roots); return roots; }