diff options
| -rw-r--r-- | src/libstore/gc.cc | 263 | ||||
| -rw-r--r-- | src/libstore/local-store.hh | 6 |
2 files changed, 138 insertions, 131 deletions
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc index fbf842350..4385e4456 100644 --- a/src/libstore/gc.cc +++ b/src/libstore/gc.cc @@ -396,24 +396,17 @@ struct LocalStore::GCState GCResults & results; PathSet roots; PathSet tempRoots; - PathSet deleted; - PathSet live; - PathSet busy; - PathSet invalidated; + PathSet dead; + PathSet alive; bool gcKeepOutputs; bool gcKeepDerivations; unsigned long long bytesInvalidated; + Path trashDir; + bool shouldDelete; GCState(GCResults & results_) : results(results_), bytesInvalidated(0) { } }; -static bool shouldDelete(GCOptions::GCAction action) -{ - return action == GCOptions::gcDeleteDead - || action == GCOptions::gcDeleteSpecific; -} - - bool LocalStore::isActiveTempFile(const GCState & state, const Path & path, const string & suffix) { @@ -424,152 +417,148 @@ bool LocalStore::isActiveTempFile(const GCState & state, void LocalStore::deleteGarbage(GCState & state, const Path & path) { - printMsg(lvlInfo, format("deleting `%1%'") % path); unsigned long long bytesFreed; deletePathWrapped(path, bytesFreed); state.results.bytesFreed += bytesFreed; } -bool LocalStore::tryToDelete(GCState & state, const Path & path) +void LocalStore::deletePathRecursive(GCState & state, const Path & path) { checkInterrupt(); - if (path == linksDir) return true; + unsigned long long size = 0; + + if (isValidPath(path)) { + PathSet referrers; + queryReferrers(path, referrers); + foreach (PathSet::iterator, i, referrers) + if (*i != path) deletePathRecursive(state, *i); + size = queryPathInfo(path).narSize; + invalidatePathChecked(path); + } struct stat st; if (lstat(path.c_str(), &st)) { - if (errno == ENOENT) return true; + if (errno == ENOENT) return; throw SysError(format("getting status of %1%") % path); } - if (state.deleted.find(path) != state.deleted.end()) return true; - if (state.live.find(path) != state.live.end()) return false; + printMsg(lvlInfo, format("deleting `%1%'") % path); - startNest(nest, lvlDebug, format("considering whether to delete `%1%'") % path); + /* If the path is not a regular file or symlink, move it to the + trash directory. The move is to ensure that later (when we're + not holding the global GC lock) we can delete the path without + being afraid that the path has become alive again. Otherwise + delete it right away. */ + if (S_ISDIR(st.st_mode)) { + // Estimate the amount freed using the narSize field. FIXME: + // if the path was not valid, need to determine the actual + // size. + state.bytesInvalidated += size; + makeMutable(path.c_str()); + // Mac OS X cannot rename directories if they are read-only. + if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1) + throw SysError(format("making `%1%' writable") % path); + Path tmp = state.trashDir + "/" + baseNameOf(path); + if (rename(path.c_str(), tmp.c_str())) + throw SysError(format("unable to rename `%1%' to `%2%'") % path % tmp); + } else + deleteGarbage(state, path); + + if (state.results.bytesFreed + state.bytesInvalidated > state.options.maxFreed) { + printMsg(lvlInfo, format("deleted or invalidated more than %1% bytes; stopping") % state.options.maxFreed); + throw GCLimitReached(); + } +} - /* If gc-keep-outputs and gc-keep-derivations are both set, we can - have cycles in the liveness graph, so we need to treat such - strongly connected components as a single unit (‘paths’). That - is, we can delete the elements of ‘paths’ only if all referrers - of ‘paths’ are garbage. */ - PathSet paths, referrers; - Paths pathsSorted; - if (isValidPath(path)) { +bool LocalStore::canReachRoot(GCState & state, PathSet & visited, const Path & path) +{ + if (visited.find(path) != visited.end()) return false; - /* Add derivers and outputs of ‘path’ to ‘paths’. */ - PathSet todo; - todo.insert(path); - while (!todo.empty()) { - Path p = *todo.begin(); - assertStorePath(p); - todo.erase(p); - if (paths.find(p) != paths.end()) continue; - paths.insert(p); - /* If gc-keep-derivations is set and this is a derivation, - then don't delete the derivation if any of the outputs - are live. */ - if (state.gcKeepDerivations && isDerivation(p)) { - PathSet outputs = queryDerivationOutputs(p); - foreach (PathSet::iterator, i, outputs) - if (isValidPath(*i) && queryDeriver(*i) == p) todo.insert(*i); - } - /* If gc-keep-outputs is set, then don't delete this path - if there are derivers of this path that are not - garbage. */ - if (state.gcKeepOutputs) { - PathSet derivers = queryValidDerivers(p); - foreach (PathSet::iterator, i, derivers) todo.insert(*i); - } - } + if (state.alive.find(path) != state.alive.end()) { + return true; } - else { - /* A lock file belonging to a path that we're building right - now isn't garbage. */ - if (isActiveTempFile(state, path, ".lock")) return false; - - /* Don't delete .chroot directories for derivations that are - currently being built. */ - if (isActiveTempFile(state, path, ".chroot")) return false; + if (state.dead.find(path) != state.dead.end()) { + return false; + } - paths.insert(path); + if (state.roots.find(path) != state.roots.end()) { + printMsg(lvlDebug, format("cannot delete `%1%' because it's a root") % path); + state.alive.insert(path); + return true; } - /* Check if any path in ‘paths’ is a root. */ - foreach (PathSet::iterator, i, paths) - if (state.roots.find(*i) != state.roots.end()) { - printMsg(lvlDebug, format("cannot delete `%1%' because it's a root") % *i); - goto isLive; - } + visited.insert(path); - /* Recursively try to delete the referrers of this strongly - connected component. If any referrer can't be deleted, then - these paths can't be deleted either. */ - foreach (PathSet::iterator, i, paths) - if (isValidPath(*i)) queryReferrers(*i, referrers); + if (!isValidPath(path)) return false; - foreach (PathSet::iterator, i, referrers) - if (paths.find(*i) == paths.end() && !tryToDelete(state, *i)) { - printMsg(lvlDebug, format("cannot delete `%1%' because it has live referrers") % *i); - goto isLive; - } + PathSet incoming; - /* The paths are garbage, so delete them. */ - pathsSorted = topoSortPaths(*this, paths); - foreach (Paths::iterator, i, pathsSorted) { - if (shouldDelete(state.options.action)) { - - /* If it's a valid path that's not a regular file or - symlink, invalidate it, rename it, and schedule it for - deletion. The renaming is to ensure that later (when - we're not holding the global GC lock) we can delete the - path without being afraid that the path has become - alive again. Otherwise delete it right away. */ - if (isValidPath(*i)) { - if (S_ISDIR(st.st_mode)) { - printMsg(lvlInfo, format("invalidating `%1%'") % *i); - // Estimate the amount freed using the narSize field. - state.bytesInvalidated += queryPathInfo(*i).narSize; - invalidatePathChecked(*i); - makeMutable(i->c_str()); - // Mac OS X cannot rename directories if they are read-only. - if (chmod(i->c_str(), st.st_mode | S_IWUSR) == -1) - throw SysError(format("making `%1%' writable") % *i); - Path tmp = (format("%1%-gc-%2%") % *i % getpid()).str(); - if (rename(i->c_str(), tmp.c_str())) - throw SysError(format("unable to rename `%1%' to `%2%'") % *i % tmp); - state.invalidated.insert(tmp); - } else { - invalidatePathChecked(*i); - deleteGarbage(state, *i); - } - } else - deleteGarbage(state, *i); + /* Don't delete this path if any of its referrers are alive. */ + queryReferrers(path, incoming); - if (state.results.bytesFreed + state.bytesInvalidated > state.options.maxFreed) { - printMsg(lvlInfo, format("deleted or invalidated more than %1% bytes; stopping") % state.options.maxFreed); - throw GCLimitReached(); + /* If gc-keep-derivations is set and this is a derivation, then + don't delete the derivation if any of the outputs are alive. */ + if (state.gcKeepDerivations && isDerivation(path)) { + PathSet outputs = queryDerivationOutputs(path); + foreach (PathSet::iterator, i, outputs) + if (isValidPath(*i) && queryDeriver(*i) == path) + incoming.insert(*i); + } + + /* If gc-keep-outputs is set, then don't delete this path if there + are derivers of this path that are not garbage. */ + if (state.gcKeepOutputs) { + PathSet derivers = queryValidDerivers(path); + foreach (PathSet::iterator, i, derivers) + incoming.insert(*i); + } + + foreach (PathSet::iterator, i, incoming) + if (*i != path) + if (canReachRoot(state, visited, *i)) { + state.alive.insert(path); + return true; } - } else - printMsg(lvlTalkative, format("would delete `%1%'") % *i); + return false; +} - state.deleted.insert(*i); - if (state.options.action != GCOptions::gcReturnLive) - state.results.paths.insert(*i); - } - return true; +void LocalStore::tryToDelete(GCState & state, const Path & path) +{ + checkInterrupt(); - isLive: - foreach (PathSet::iterator, i, paths) { - state.live.insert(*i); - if (state.options.action == GCOptions::gcReturnLive) - state.results.paths.insert(*i); + if (path == linksDir || path == state.trashDir) return; + + startNest(nest, lvlDebug, format("considering whether to delete `%1%'") % path); + + if (!isValidPath(path)) { + /* A lock file belonging to a path that we're building right + now isn't garbage. */ + if (isActiveTempFile(state, path, ".lock")) return; + + /* Don't delete .chroot directories for derivations that are + currently being built. */ + if (isActiveTempFile(state, path, ".chroot")) return; + } + + PathSet visited; + + if (canReachRoot(state, visited, path)) { + printMsg(lvlDebug, format("cannot delete `%1%' because it's still reachable") % path); + } else { + /* No path we visited was a root, so everything is garbage. + But we only delete ‘path’ and its referrers here so that + ‘nix-store --delete’ doesn't have the unexpected effect of + recursing into derivations and outputs. */ + state.dead.insert(visited.begin(), visited.end()); + if (state.shouldDelete) + deletePathRecursive(state, path); } - return false; } @@ -625,7 +614,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) { GCState state(results); state.options = options; - + state.trashDir = settings.nixStore + "/trash"; state.gcKeepOutputs = settings.gcKeepOutputs; state.gcKeepDerivations = settings.gcKeepDerivations; @@ -638,6 +627,8 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) state.gcKeepDerivations = false; } + state.shouldDelete = options.action == GCOptions::gcDeleteDead || options.action == GCOptions::gcDeleteSpecific; + /* Acquire the global GC root. This prevents a) New roots from being added. b) Processes from creating new temporary root files. */ @@ -668,6 +659,8 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) increase, since we hold locks on everything. So everything that is not reachable from `roots'. */ + if (state.shouldDelete) createDirs(state.trashDir); + /* Now either delete all garbage paths, or just the specified paths (for gcDeleteSpecific). */ @@ -675,13 +668,14 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) foreach (PathSet::iterator, i, options.pathsToDelete) { assertStorePath(*i); - if (!tryToDelete(state, *i)) + tryToDelete(state, *i); + if (state.dead.find(*i) == state.dead.end()) throw Error(format("cannot delete path `%1%' since it is still alive") % *i); } } else if (options.maxFreed > 0) { - if (shouldDelete(state.options.action)) + if (state.shouldDelete) printMsg(lvlError, format("deleting garbage...")); else printMsg(lvlError, format("determining live/dead paths...")); @@ -727,13 +721,22 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) } } + if (state.options.action == GCOptions::gcReturnLive) { + state.results.paths = state.alive; + return; + } + + if (state.options.action == GCOptions::gcReturnDead) { + state.results.paths = state.dead; + return; + } + /* Allow other processes to add to the store from here on. */ fdGCLock.close(); - /* Delete the invalidated paths now that the lock has been - released. */ - foreach (PathSet::iterator, i, state.invalidated) - deleteGarbage(state, *i); + /* Delete the trash directory. */ + printMsg(lvlInfo, format("deleting `%1%'") % state.trashDir); + deleteGarbage(state, state.trashDir); /* Clean up the links directory. */ if (options.action == GCOptions::gcDeleteDead || options.action == GCOptions::gcDeleteSpecific) { diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh index ebf3f6e2b..bb5a9143c 100644 --- a/src/libstore/local-store.hh +++ b/src/libstore/local-store.hh @@ -276,7 +276,11 @@ private: void deleteGarbage(GCState & state, const Path & path); - bool tryToDelete(GCState & state, const Path & path); + void tryToDelete(GCState & state, const Path & path); + + bool canReachRoot(GCState & state, PathSet & visited, const Path & path); + + void deletePathRecursive(GCState & state, const Path & path); bool isActiveTempFile(const GCState & state, const Path & path, const string & suffix); |