diff options
Diffstat (limited to 'src/libstore')
| -rw-r--r-- | src/libstore/gc.cc | 191 |
1 files changed, 97 insertions, 94 deletions
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc index 88b7bec32677..0e0c15934ec5 100644 --- a/src/libstore/gc.cc +++ b/src/libstore/gc.cc @@ -448,67 +448,43 @@ bool LocalStore::tryToDelete(GCState & state, const Path & path) startNest(nest, lvlDebug, format("considering whether to delete `%1%'") % path); - if (state.roots.find(path) != state.roots.end()) { - printMsg(lvlDebug, format("cannot delete `%1%' because it's a root") % path); - goto isLive; - } + /* 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; if (isValidPath(path)) { - /* Recursively try to delete the referrers of this path. If - any referrer can't be deleted, then this path can't be - deleted either. */ - PathSet referrers; - queryReferrers(path, referrers); - foreach (PathSet::iterator, i, referrers) - if (*i != path && !tryToDelete(state, *i)) { - printMsg(lvlDebug, format("cannot delete `%1%' because it has live referrers") % path); - goto isLive; + /* 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)) todo.insert(*i); } - - /* 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(path)) { - PathSet outputs = queryDerivationOutputs(path); - foreach (PathSet::iterator, i, outputs) - if (!tryToDelete(state, *i)) { - printMsg(lvlDebug, format("cannot delete derivation `%1%' because its output `%2%' is alive") % path % *i); - goto isLive; - } - } - - /* If gc-keep-derivations and gc-keep-outputs are both set, - it's possible that the path has already been deleted (due - to the recursion below), so bail out. */ - if (!pathExists(path)) return true; - - /* 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, deriver, derivers) { - /* Break an infinite recursion if gc-keep-derivations - and gc-keep-outputs are both set by tentatively - assuming that this path is garbage. This is a safe - assumption because at this point, the only thing - that can prevent it from being garbage is the - deriver. Since tryToDelete() works "upwards" - through the dependency graph, it won't encouter - this path except in the call to tryToDelete() in - the gc-keep-derivation branch. */ - state.deleted.insert(path); - if (!tryToDelete(state, *deriver)) { - state.deleted.erase(path); - printMsg(lvlDebug, format("cannot delete `%1%' because its deriver `%2%' is alive") % path % *deriver); - goto isLive; - } + /* 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); } } } else { - /* A lock file belonging to a path that we're building right now isn't garbage. */ if (isActiveTempFile(state, path, ".lock")) return false; @@ -517,55 +493,80 @@ bool LocalStore::tryToDelete(GCState & state, const Path & path) currently being built. */ if (isActiveTempFile(state, path, ".chroot")) return false; + paths.insert(path); } - /* The path is garbage, so delete it. */ - 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(path)) { - if (S_ISDIR(st.st_mode)) { - printMsg(lvlInfo, format("invalidating `%1%'") % path); - // Estimate the amount freed using the narSize field. - state.bytesInvalidated += queryPathInfo(path).narSize; - invalidatePathChecked(path); - 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 = (format("%1%-gc-%2%") % path % getpid()).str(); - if (rename(path.c_str(), tmp.c_str())) - throw SysError(format("unable to rename `%1%' to `%2%'") % path % tmp); - state.invalidated.insert(tmp); - } else { - invalidatePathChecked(path); - deleteGarbage(state, path); - } - } else - deleteGarbage(state, path); + /* 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; + } - 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(); + /* 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); + + 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; } - } else - printMsg(lvlTalkative, format("would delete `%1%'") % path); + /* The paths are garbage, so delete them. */ + foreach (PathSet::iterator, i, paths) { + 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); + + 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(); + } + + } else + printMsg(lvlTalkative, format("would delete `%1%'") % *i); + + state.deleted.insert(*i); + if (state.options.action != GCOptions::gcReturnLive) + state.results.paths.insert(*i); + } - state.deleted.insert(path); - if (state.options.action != GCOptions::gcReturnLive) - state.results.paths.insert(path); return true; isLive: - state.live.insert(path); - if (state.options.action == GCOptions::gcReturnLive) - state.results.paths.insert(path); + foreach (PathSet::iterator, i, paths) { + state.live.insert(*i); + if (state.options.action == GCOptions::gcReturnLive) + state.results.paths.insert(*i); + } return false; } @@ -733,8 +734,10 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) deleteGarbage(state, *i); /* Clean up the links directory. */ - printMsg(lvlError, format("deleting unused links...")); - removeUnusedLinks(state); + if (options.action == GCOptions::gcDeleteDead || options.action == GCOptions::gcDeleteSpecific) { + printMsg(lvlError, format("deleting unused links...")); + removeUnusedLinks(state); + } } |