diff options
| -rw-r--r-- | src/libstore/build.cc | 30 | ||||
| -rw-r--r-- | src/libstore/local-store.cc | 4 | ||||
| -rw-r--r-- | src/libstore/pathlocks.cc | 6 | ||||
| -rw-r--r-- | src/libstore/pathlocks.hh | 6 |
4 files changed, 24 insertions, 22 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 392b494e65eb..cc69ff1c74bf 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -1335,19 +1335,6 @@ void DerivationGoal::tryToBuild() { trace("trying to build"); - /* Check for the possibility that some other goal in this process - has locked the output since we checked in haveDerivation(). - (It can't happen between here and the lockPaths() call below - because we're not allowing multi-threading.) If so, put this - goal to sleep until another goal finishes, then try again. */ - for (auto & i : drv->outputs) - if (pathIsLockedByMe(worker.store.toRealPath(i.second.path))) { - debug(format("putting derivation '%1%' to sleep because '%2%' is locked by another goal") - % drvPath % i.second.path); - worker.waitForAnyGoal(shared_from_this()); - return; - } - /* Obtain locks on all output paths. The locks are automatically released when we exit this function or Nix crashes. If we can't acquire the lock, then continue; hopefully some other @@ -3739,6 +3726,17 @@ void SubstitutionGoal::tryToRun() return; } + /* If the store path is already locked (probably by a + DerivationGoal), then put this goal to sleep. Note: we don't + acquire a lock here since that breaks addToStore(), so below we + handle an AlreadyLocked exception from addToStore(). The check + here is just an optimisation to prevent having to redo a + download due to a locked path. */ + if (pathIsLockedByMe(worker.store.toRealPath(storePath))) { + worker.waitForAWhile(shared_from_this()); + return; + } + maintainRunningSubstitutions = std::make_unique<MaintainCount<uint64_t>>(worker.runningSubstitutions); worker.updateProgress(); @@ -3778,6 +3776,12 @@ void SubstitutionGoal::finished() try { promise.get_future().get(); + } catch (AlreadyLocked & e) { + /* Probably a DerivationGoal is already building this store + path. Sleep for a while and try again. */ + state = &SubstitutionGoal::init; + worker.waitForAWhile(shared_from_this()); + return; } catch (Error & e) { printError(e.msg()); diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index 7afecc1cfc62..8a79fc7235fa 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -992,8 +992,8 @@ void LocalStore::addToStore(const ValidPathInfo & info, const ref<std::string> & /* Lock the output path. But don't lock if we're being called from a build hook (whose parent process already acquired a lock on this path). */ - Strings locksHeld = tokenizeString<Strings>(getEnv("NIX_HELD_LOCKS")); - if (find(locksHeld.begin(), locksHeld.end(), info.path) == locksHeld.end()) + static auto locksHeld = tokenizeString<PathSet>(getEnv("NIX_HELD_LOCKS")); + if (!locksHeld.count(info.path)) outputLock.lockPaths({realPath}); if (repair || !isValidPath(info.path)) { diff --git a/src/libstore/pathlocks.cc b/src/libstore/pathlocks.cc index 587f29598851..08d1efdbeb01 100644 --- a/src/libstore/pathlocks.cc +++ b/src/libstore/pathlocks.cc @@ -113,8 +113,10 @@ bool PathLocks::lockPaths(const PathSet & _paths, { auto lockedPaths(lockedPaths_.lock()); - if (lockedPaths->count(lockPath)) - throw Error("deadlock: trying to re-acquire self-held lock '%s'", lockPath); + if (lockedPaths->count(lockPath)) { + if (!wait) return false; + throw AlreadyLocked("deadlock: trying to re-acquire self-held lock '%s'", lockPath); + } lockedPaths->insert(lockPath); } diff --git a/src/libstore/pathlocks.hh b/src/libstore/pathlocks.hh index 2a7de611446e..db51f950a320 100644 --- a/src/libstore/pathlocks.hh +++ b/src/libstore/pathlocks.hh @@ -2,10 +2,8 @@ #include "util.hh" - namespace nix { - /* Open (possibly create) a lock file and return the file descriptor. -1 is returned if create is false and the lock could not be opened because it doesn't exist. Any other error throws an exception. */ @@ -18,6 +16,7 @@ enum LockType { ltRead, ltWrite, ltNone }; bool lockFile(int fd, LockType lockType, bool wait); +MakeError(AlreadyLocked, Error); class PathLocks { @@ -38,9 +37,6 @@ public: void setDeletion(bool deletePaths); }; - -// FIXME: not thread-safe! bool pathIsLockedByMe(const Path & path); - } |