Remove dead makeMutable() function

This code wasn't being compiled because the #if conditional didn't
trigger. Anyway, Nix 0.15 is 15 years old so we don't need to keep
this around.

src/libstore/local-store.cc

@@ -42,7 +42,6 @@
 # include <sched.h>
 # include <sys/statvfs.h>
 # include <sys/mount.h>
-# include <sys/ioctl.h>
 #endif
 
 #ifdef __CYGWIN__
@@ -366,8 +365,6 @@ LocalStore::LocalStore(
            have performed the upgrade already. */
         curSchema = getSchema();
 
-        if (curSchema < 7) { upgradeStore7(); }
-
         openDB(*state, false);
 
         if (curSchema < 8) {
@@ -1596,62 +1593,6 @@ std::optional<TrustedFlag> LocalStore::isTrustedClient()
 }
 
 
-#if defined(FS_IOC_SETFLAGS) && defined(FS_IOC_GETFLAGS) && defined(FS_IMMUTABLE_FL)
-
-static void makeMutable(const Path & path)
-{
-    checkInterrupt();
-
-    auto st = lstat(path);
-
-    if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode)) return;
-
-    if (S_ISDIR(st.st_mode)) {
-        for (auto & i : readDirectory(path))
-            makeMutable(path + "/" + i.name);
-    }
-
-    /* The O_NOFOLLOW is important to prevent us from changing the
-       mutable bit on the target of a symlink (which would be a
-       security hole). */
-    AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_NOFOLLOW
-#ifndef _WIN32
-        | O_CLOEXEC
-#endif
-        );
-    if (fd == INVALID_DESCRIPTOR) {
-        if (errno == ELOOP) return; // it's a symlink
-        throw SysError("opening file '%1%'", path);
-    }
-
-    unsigned int flags = 0, old;
-
-    /* Silently ignore errors getting/setting the immutable flag so
-       that we work correctly on filesystems that don't support it. */
-    if (ioctl(fd, FS_IOC_GETFLAGS, &flags)) return;
-    old = flags;
-    flags &= ~FS_IMMUTABLE_FL;
-    if (old == flags) return;
-    if (ioctl(fd, FS_IOC_SETFLAGS, &flags)) return;
-}
-
-/* Upgrade from schema 6 (Nix 0.15) to schema 7 (Nix >= 1.3). */
-void LocalStore::upgradeStore7()
-{
-    if (!isRootUser()) return;
-    printInfo("removing immutable bits from the Nix store (this may take a while)...");
-    makeMutable(realStoreDir);
-}
-
-#else
-
-void LocalStore::upgradeStore7()
-{
-}
-
-#endif
-
-
 void LocalStore::vacuumDB()
 {
     auto state(_state.lock());

src/libstore/local-store.hh

@@ -373,8 +373,6 @@ private:
 
     void updatePathInfo(State & state, const ValidPathInfo & info);
 
-    void upgradeStore6();
-    void upgradeStore7();
     PathSet queryValidPathsOld();
     ValidPathInfo queryPathInfoOld(const Path & path);