5622892013-09-20Henrik Grubbström (Grubba) // // Unified file system garbage collector. // // 2013-09-12 Henrik Grubbström // #if constant(Filesystem.Monitor.basic)
3c5dd42013-10-02Henrik Grubbström (Grubba) // #define FSGC_DEBUG
5622892013-09-20Henrik Grubbström (Grubba) // #define FSGC_PRETEND #ifdef FSGC_DEBUG #define GC_WERR(X...) werror(X) #else #define GC_WERR(X...) #endif /* Some notes: * * There are multiple data for a file that may affect the garbage policy: * * * The age of the file. * * * The size of the file. * * Garbage collection for a root may be triggered by several factors: * * * A maxium age for a file has been reached. * * * Too many files under a root. * * * The total size of the files under a root is too large. * * Symlinks are not followed and not garbage collected due * to the inherent risks of escaping directory structures * and/or removing manually added stuff. */ //! Filesystem garbage collector for a single root directory. class FSGarb { inherit Filesystem.Monitor.basic : basic; int num_files; int total_size;
431a482013-09-26Henrik Grubbström (Grubba)  string modid;
5622892013-09-20Henrik Grubbström (Grubba)  string root; int max_age; int max_files; int max_size; mapping(string:object) handle_lookup = ([]); ADT.Priority_queue pending_gc = ADT.Priority_queue();
e9b8c22016-11-17Henrik Grubbström (Grubba)  //! If set, move files to this directory instead of deleting them. //! //! If set to @[root] or @expr{""@} keep the files as is. string quarantine;
5622892013-09-20Henrik Grubbström (Grubba)  protected int rm(string path) {
e9b8c22016-11-17Henrik Grubbström (Grubba)  GC_WERR("FSGC: Zap %O\n", path); if (quarantine) { if ((quarantine == root) || (quarantine == "")) return 0; if (!has_prefix(path, root)) return 0; string rel = path[sizeof(root)..]; // First try the trivial case. if (mv(path, quarantine + rel)) return 1; string dirs = dirname(rel); if (sizeof(dirs)) { if (Stdio.mkdirhier(quarantine + dirs)) { // Try again with the directory existing. if (mv(path, quarantine + rel)) return 1; } } // Different filesystems? if (Stdio.cp(path, quarantine + rel)) { return predef::rm(path); } werror("FSGC: Failed to copy file %O to %O: %s.\n", path, quarantine + rel, strerror(errno())); return 0; } else { return predef::rm(path); }
5622892013-09-20Henrik Grubbström (Grubba)  } void check_threshold() { GC_WERR("FSGC: Checking thresholds...\n" " total_size: %d max_size: %d\n" " num_files: %d max_files: %d\n", total_size, max_size, num_files, max_files); while ((max_size && (total_size > max_size)) || (max_files && (num_files > max_files))) { GC_WERR("FSGC: Filesystem limits exceeded forcing early removal.\n"); if (!zap_one_file()) break; } } protected int zap_one_file() { if (!sizeof(pending_gc)) return 0; // Pop the next pending file from the queue. Monitor m = pending_gc->pop(); m_delete(handle_lookup, m->path); // Account for the deletion immediately, and // make sure it isn't counted twice. int bytes = m->st->size; m->st->size = 0; m->st->isreg = 0; GC_WERR("Deleting file %O...\n", m->path); if (rm(m->path)) { num_files--; total_size -= bytes; // Make sure the deletion is notified properly soon. m->next_poll = time(1); monitor_queue->adjust(m); } else { GC_WERR("Failed to delete file %O: %s\n", m->path, strerror(errno())); // Restore the state in case the file is altered externally. m->st->size = bytes; m->st->isreg = 1; } return 1; } int st_to_pri(Stdio.Stat st) { return st->mtime - st->size / 1024; } protected void remove_pending(Monitor m) { // Register us for threshold-based deletion. object handle = m_delete(handle_lookup, m->path); if (handle) { pending_gc->adjust_pri(handle, -0x80000000); pending_gc->pop(); } } protected class Monitor { inherit basic::Monitor; protected void create(string path, MonitorFlags flags, int max_dir_check_interval, int file_interval_factor, int stable_time) { ::create(path, flags, max_dir_check_interval, file_interval_factor, stable_time); GC_WERR("%O->create(%O, %O, %O, %O, %O)\n", this_object(), path, flags, max_dir_check_interval, file_interval_factor, stable_time); } void check_for_release(int mask, int flags) { GC_WERR("%O->check_for_relase(0x%x, 0x%x)\n", this_object(), mask, flags); ::check_for_release(mask, flags); if (!monitors[path]) { // We've been relased. // Make sure to update our parent (if any) soon. array a = path/"/"; Monitor m = monitors[canonic_path(a[..sizeof(a)-2]*"/")]; if (m) { GC_WERR("Waking up our parent dir: %O\n", m); m->next_poll = time(1)-1; monitor_queue->adjust(m); } } } protected void file_exists(string path, Stdio.Stat st) { ::file_exists(path, st); // Make sure we get the stable change callback... last_change = st->mtime; if (st->isreg) { num_files++; total_size += st->size; // Register us for threadhold-based deletion. handle_lookup[path] = pending_gc->push(st_to_pri(st), this); check_threshold(); } } // NB: Needs to be visible so that reconfigure() can call it. void update(Stdio.Stat st) { int delta = max_dir_check_interval || basic::max_dir_check_interval; if (!next_poll) { // Attempt to distribute polls evenly at startup. delta = 1 + random(delta); if (st) { last_change = st->mtime; } } ::update(st); // We're only interested in stable time, so there's no reason // to scan as frequently as the default implementation. if (last_change <= time(1)) { // Time until stable. int d = last_change + (stable_time || basic::stable_time) - time(1); GC_WERR("%O: last: %s, d: %d, delta: %d\n", this_object(), ctime(last_change) - "\n", d, delta); if (d < 0) d = 1; if (d < delta) delta = d; } next_poll = time(1) + (delta || 1); GC_WERR("%O->update(%O) ==> next: %s\n", this_object(), st, ctime(next_poll) - "\n"); monitor_queue->adjust(this); } protected string _sprintf(int c) { return sprintf("FSGarb.Monitor(%O, %O, last: %d, next: %s, st: %O)", path, flags, last_change, ctime(next_poll) - "\n", st); } int(0..1) check(MonitorFlags|void flags) { int(0..1) ret = ::check(flags); return ret; } int(0..1) status_change(Stdio.Stat old_st, Stdio.Stat st, MonitorFlags old_flags, MonitorFlags flags) { GC_WERR("Status change %O(0x%x) ==> %O(0x%x) for %O!\n", old_st, old_flags, st, flags, this_object()); int res = ::status_change(old_st, st, old_flags, flags); if (st->isdir && (flags & MF_RECURSE)) { foreach(files, string file) { file = canonic_path(Stdio.append_path(path, file)); if (!monitors[file]) { // Lost update due to race-condition: // // Exist ==> Deleted ==> Exists // // with no update of directory inbetween. // // Create the lost submonitor again. res = 1; monitor(file, old_flags | MF_AUTO | MF_HARD, max_dir_check_interval, file_interval_factor, stable_time); monitors[file]->check(); } } } num_files += st->isreg - old_st->isreg; if (old_st->isreg) { total_size -= old_st->size; if (!st->isreg) { remove_pending(this); } } if (st->isreg) { total_size += st->size; // Register us for threshold-based deletion. if (!old_st->isreg) { handle_lookup[path] = pending_gc->push(st_to_pri(st), this); } else { object handle = handle_lookup[path]; if (handle && (st_to_pri(st) != st_to_pri(old_st))) { pending_gc->adjust_pri(handle, st_to_pri(st)); } } } check_threshold(); return res; } void file_created(string path, Stdio.Stat st) { GC_WERR("File %O %O created (%O).\n", path, st, this_object()); if (st->isreg) { num_files++; total_size += st->size; // Register us for threshold-based deletion. handle_lookup[path] = pending_gc->push(st_to_pri(st), this); check_threshold(); } } void file_deleted(string path, Stdio.Stat old_st) { GC_WERR("File %O %O deleted (%O).\n", path, old_st, this_object()); if (old_st->isreg) { num_files--; total_size -= old_st->size; remove_pending(this); check_threshold(); } } }
6b2b622017-11-17Anders Johansson  constant DefaultMonitor = Monitor;
431a482013-09-26Henrik Grubbström (Grubba)  protected void create(string modid, string path, int max_age,
e9b8c22016-11-17Henrik Grubbström (Grubba)  int|void max_size, int|void max_files, string|void quarantine)
5622892013-09-20Henrik Grubbström (Grubba)  { GC_WERR("FSGC: Max age: %d\n", max_age); GC_WERR("FSGC: Max size: %d\n", max_size); GC_WERR("FSGC: Max files: %d\n", max_files);
431a482013-09-26Henrik Grubbström (Grubba)  this_program::modid = modid;
5622892013-09-20Henrik Grubbström (Grubba)  this_program::max_age = max_age; this_program::max_size = max_size; this_program::max_files = max_files;
431a482013-09-26Henrik Grubbström (Grubba)  root = canonic_path(path);
5622892013-09-20Henrik Grubbström (Grubba) 
e9b8c22016-11-17Henrik Grubbström (Grubba)  if (quarantine) { if (sizeof(quarantine)) { quarantine = canonic_path(quarantine); } this::quarantine = quarantine; }
431a482013-09-26Henrik Grubbström (Grubba)  ::create(max_age/file_interval_factor, 0, max_age);
5622892013-09-20Henrik Grubbström (Grubba) 
60f1a32013-09-27Henrik Grubbström (Grubba)  // Workaround for too strict type-check in Pike 7.8. int flags = 3; monitor(root, flags);
5622892013-09-20Henrik Grubbström (Grubba)  } void stable_data_change(string path, Stdio.Stat st) {
146dc62013-09-25Henrik Grubbström (Grubba)  if (path == root) return;
ca76c52017-11-16Henrik Grubbström (Grubba)  GC_WERR("FSGC: Deleting stale file: %O\n", path);
6b2b622017-11-17Anders Johansson  #if 0 // If we ever use accelerated notifications again.
fce9912017-11-15Anders Johansson  // Override accelerated stable change notification.
94cf532017-11-16Henrik Grubbström (Grubba)  if (st->mtime >= time(1) - stable_time) {
fce9912017-11-15Anders Johansson  GC_WERR("FSGC: Keeping file: %O\n", path);
8445982017-11-16Henrik Grubbström (Grubba)  // Remove the stable notification marker, and reschedule.
1d38ee2017-11-16Henrik Grubbström (Grubba)  Monitor m = monitor(path, MF_AUTO); m->last_change = st->mtime; // m->update(st); m->check(); // Force an update().
fce9912017-11-15Anders Johansson  return; }
6b2b622017-11-17Anders Johansson #endif
5622892013-09-20Henrik Grubbström (Grubba)  rm(path); } void reconfigure(int new_max_age, int|void new_max_size, int|void new_max_files) { if (!zero_type(new_max_size)) { GC_WERR("FSGC: New max size: %d\n", new_max_size); max_size = new_max_size; } if (!zero_type(new_max_files)) { GC_WERR("FSGC: New max files: %d\n", new_max_files); max_files = new_max_files; } if (new_max_age != max_age) { GC_WERR("FSGC: New max age: %d\n", new_max_age); this_program::max_age = new_max_age; int old_stable_time = stable_time; set_max_dir_check_interval(stable_time = new_max_age); if (stable_time < old_stable_time) { // We need to adjust the scan times for the monitors. foreach(values(monitors), Monitor m) { m->next_poll = 0; m->update(m->st); } } } check_threshold(); } int check(mixed ... args) { int res = ::check(@args); GC_WERR("FSGC: check(%{%O, %}) ==> %O\n", args, res); return res; } protected string _sprintf(int c, mapping|void opts) { return sprintf("FSGarb(%O, %d)", root, stable_time); } array(Stdio.Stat) get_stats() { return filter(values(monitors)->st, lambda(Stdio.Stat st) { return st && st->isreg; }); } } mapping(string:FSGarb) fsgarbs = ([]); Thread.Thread meta_fsgc_thread; void meta_fsgc() { // Sleep a bit to avoid the startup race. sleep(60); while(meta_fsgc_thread) { int max_sleep = 60; foreach(fsgarbs; string id; FSGarb g) { int seconds = g && g->check(); if (seconds < max_sleep) max_sleep = seconds; } if (max_sleep < 1) max_sleep = 1; GC_WERR("FSGC: Sleeping %d seconds...\n", max_sleep); while(meta_fsgc_thread && max_sleep--) { sleep(1); } } } //! Wrapper keeping a @[FSGarb] alive. //! //! When this object is destructed (eg by refcount), the corresponding //! @[FSGarb] will be killed. This is to make sure stale @[FSGarb]s aren't //! left running after module reloads or reconfigurations. class FSGarbWrapper(string id) { protected void destroy() { GC_WERR("FSGC: FSGarbWrapper %O destructed.\n", id); FSGarb g = m_delete(fsgarbs, id); if (g) destruct(g); } protected string _sprintf(int c, mapping|void opts) { return sprintf("FSGarbWrapper(%O)", id); } void reconfigure(int max_age, int|void max_size, int|void max_files) { FSGarb g = fsgarbs[id]; if (g) g->reconfigure(max_age, max_size, max_files); } }
431a482013-09-26Henrik Grubbström (Grubba) FSGarbWrapper register_fsgarb(string modid, string path, int max_age,
e9b8c22016-11-17Henrik Grubbström (Grubba)  int|void max_size, int|void max_files, string|void quarantine)
5622892013-09-20Henrik Grubbström (Grubba) {
9ab0b32013-09-27Henrik Grubbström (Grubba)  if ((path == "") || (path == "/") || (max_age <= 0)) return 0;
431a482013-09-26Henrik Grubbström (Grubba)  string id = modid + "\0" + path + "\0" + gethrtime();
e9b8c22016-11-17Henrik Grubbström (Grubba)  FSGarb g = FSGarb(modid, path, max_age, max_size, max_files, quarantine);
5622892013-09-20Henrik Grubbström (Grubba)  fsgarbs[id] = g; GC_WERR("FSGC: Register garb on %O ==> id: %O\n", path, id); return FSGarbWrapper(id); } protected void start_fsgarb() { meta_fsgc_thread = Thread.Thread(meta_fsgc);
6aceb32018-04-04Jonas Walldén  Roxen.name_thread(meta_fsgc_thread, "Filesystem GC");
5622892013-09-20Henrik Grubbström (Grubba) } protected void stop_fsgarb() { Thread.Thread th = meta_fsgc_thread; if (th) { meta_fsgc_thread = UNDEFINED; th->wait();
6aceb32018-04-04Jonas Walldén  Roxen.name_thread(th, UNDEFINED);
5622892013-09-20Henrik Grubbström (Grubba)  } } #endif /* Filesystem.Monitor.basic */