TFileAdaptor/src/TStorageFactoryFile.cc

0001 #include "IOPool/TFileAdaptor/interface/TStorageFactoryFile.h"
0002 #include "Utilities/StorageFactory/interface/Storage.h"
0003 #include "Utilities/StorageFactory/interface/StorageFactory.h"
0004 #include "Utilities/StorageFactory/interface/StorageAccount.h"
0005 #include "Utilities/StorageFactory/interface/StatisticsSenderService.h"
0006 #include "FWCore/ServiceRegistry/interface/Service.h"
0007 #include "FWCore/Utilities/interface/EDMException.h"
0008 #include "FWCore/Utilities/interface/ExceptionPropagate.h"
0009 #include "ReadRepacker.h"
0010 #include "TFileCacheRead.h"
0011 #include "TSystem.h"
0012 #include "TROOT.h"
0013 #include "TEnv.h"
0014 #include <cerrno>
0015 #include <sys/stat.h>
0016 #include <unistd.h>
0017 #include <fcntl.h>
0018 #include <iostream>
0019 #include <cassert>
0020 #include <atomic>
0021
0022 #if 0
0023 #include "TTreeCache.h"
0024 #include "TTree.h"
0025
0026 class TTreeCacheDebug : public TTreeCache {
0027 public:
0028   void dump(const char *label, const char *trailer)
0029   {
0030     Long64_t entry = fOwner->GetReadEntry();
0031     std::cerr
0032       << label << ": " << entry << " "
0033       << "{ fEntryMin=" << fEntryMin
0034       << ", fEntryMax=" << fEntryMax
0035       << ", fEntryNext=" << fEntryNext
0036       << ", fZipBytes=" << fZipBytes
0037       << ", fNbranches=" << fNbranches
0038       << ", fNReadOk=" << fNReadOk
0039       << ", fNReadMiss=" << fNReadMiss
0040       << ", fNReadPref=" << fNReadPref
0041       << ", fBranches=" << fBranches
0042       << ", fBrNames=" << fBrNames
0043       << ", fOwner=" << fOwner
0044       << ", fTree=" << fTree
0045       << ", fIsLearning=" << fIsLearning
0046       << ", fIsManual=" << fIsManual
0047       << "; fBufferSizeMin=" << fBufferSizeMin
0048       << ", fBufferSize=" << fBufferSize
0049       << ", fBufferLen=" << fBufferLen
0050       << ", fBytesToPrefetch=" << fBytesToPrefetch
0051       << ", fFirstIndexToPrefetch=" << fFirstIndexToPrefetch
0052       << ", fAsyncReading=" << fAsyncReading
0053       << ", fNseek=" << fNseek
0054       << ", fNtot=" << fNtot
0055       << ", fNb=" << fNb
0056       << ", fSeekSize=" << fSeekSize
0057       << ", fSeek=" << fSeek
0058       << ", fSeekIndex=" << fSeekIndex
0059       << ", fSeekSort=" << fSeekSort
0060       << ", fPos=" << fPos
0061       << ", fSeekLen=" << fSeekLen
0062       << ", fSeekSortLen=" << fSeekSortLen
0063       << ", fSeekPos=" << fSeekPos
0064       << ", fLen=" << fLen
0065       << ", fFile=" << fFile
0066       << ", fBuffer=" << (void *) fBuffer
0067       << ", fIsSorted=" << fIsSorted
0068       << " }\n" << trailer;
0069   }
0070 };
0071 #endif
0072
0073 using namespace edm::storage;
0074
0075 ClassImp(TStorageFactoryFile);
0076 static std::atomic<StorageAccount::Counter *> s_statsCtor = nullptr;
0077 static std::atomic<StorageAccount::Counter *> s_statsOpen = nullptr;
0078 static std::atomic<StorageAccount::Counter *> s_statsClose = nullptr;
0079 static std::atomic<StorageAccount::Counter *> s_statsFlush = nullptr;
0080 static std::atomic<StorageAccount::Counter *> s_statsStat = nullptr;
0081 static std::atomic<StorageAccount::Counter *> s_statsSeek = nullptr;
0082 static std::atomic<StorageAccount::Counter *> s_statsRead = nullptr;
0083 static std::atomic<StorageAccount::Counter *> s_statsCRead = nullptr;
0084 static std::atomic<StorageAccount::Counter *> s_statsCPrefetch = nullptr;
0085 static std::atomic<StorageAccount::Counter *> s_statsARead = nullptr;
0086 static std::atomic<StorageAccount::Counter *> s_statsXRead = nullptr;
0087 static std::atomic<StorageAccount::Counter *> s_statsWrite = nullptr;
0088 static std::atomic<StorageAccount::Counter *> s_statsCWrite = nullptr;
0089 static std::atomic<StorageAccount::Counter *> s_statsXWrite = nullptr;
0090
0091 static inline StorageAccount::Counter &storageCounter(std::atomic<StorageAccount::Counter *> &c,
0092                                                       StorageAccount::Operation operation) {
0093   static const auto token = StorageAccount::tokenForStorageClassName("tstoragefile");
0094   if (!c) {
0095     auto v = &StorageAccount::counter(token, operation);
0096     StorageAccount::Counter *expected = nullptr;
0097     c.compare_exchange_strong(expected, v);
0098   }
0099   return *c.load();
0100 }
0101
0102 TStorageFactoryFile::TStorageFactoryFile(void) : storage_() {
0103   StorageAccount::Stamp stats(storageCounter(s_statsCtor, StorageAccount::Operation::construct));
0104   stats.tick(0);
0105 }
0106
0107 // This constructor must be compatible with *all* the various built-in TFile plugins,
0108 // including TXNetFile.  This is why some arguments in the constructor is ignored.
0109 // If there's a future T*File that is incompatible with this constructor, a new
0110 // constructor will have to be added.
0111 TStorageFactoryFile::TStorageFactoryFile(const char *path,
0112                                          Option_t *option,
0113                                          const char *ftitle,
0114                                          Int_t compress,
0115                                          Int_t netopt,
0116                                          Bool_t parallelopen /* = kFALSE */)
0117     : TFile(path, "NET", ftitle, compress),  // Pass "NET" to prevent local access in base class
0118       storage_() {
0119   try {
0120     Initialize(path, option);
0121   } catch (...) {
0122     edm::threadLocalException::setException(std::current_exception());  // capture
0123   }
0124 }
0125
0126 TStorageFactoryFile::TStorageFactoryFile(const char *path,
0127                                          Option_t *option /* = "" */,
0128                                          const char *ftitle /* = "" */,
0129                                          Int_t compress /* = 1 */)
0130     : TFile(path, "NET", ftitle, compress),  // Pass "NET" to prevent local access in base class
0131       storage_() {
0132   try {
0133     Initialize(path, option);
0134   } catch (...) {
0135     edm::threadLocalException::setException(std::current_exception());  // capture
0136   }
0137 }
0138
0139 void TStorageFactoryFile::Initialize(const char *path, Option_t *option /* = "" */) {
0140   StorageAccount::Stamp stats(storageCounter(s_statsCtor, StorageAccount::Operation::construct));
0141
0142   // Enable AsyncReading.
0143   // This was the default for 5.27, but turned off by default for 5.32.
0144   // In our testing, AsyncReading is the fastest mechanism available.
0145   // In 5.32, the AsyncPrefetching mechanism is preferred, but has been a
0146   // performance hit in our "average case" tests.
0147   gEnv->SetValue("TFile.AsyncReading", 1);
0148
0149   // Parse options; at the moment we only accept read!
0150   fOption = option;
0151   fOption.ToUpper();
0152
0153   if (fOption == "NEW")
0154     fOption = "CREATE";
0155
0156   Bool_t create = (fOption == "CREATE");
0157   Bool_t recreate = (fOption == "RECREATE");
0158   Bool_t update = (fOption == "UPDATE");
0159   Bool_t read = (fOption == "READ") || (fOption == "READWRAP");
0160   Bool_t readwrap = (fOption == "READWRAP");
0161
0162   if (!create && !recreate && !update && !read) {
0163     read = true;
0164     fOption = "READ";
0165   }
0166
0167   if (recreate) {
0168     if (!gSystem->AccessPathName(path, kFileExists))
0169       gSystem->Unlink(path);
0170
0171     recreate = false;
0172     create = true;
0173     fOption = "CREATE";
0174   }
0175   assert(!recreate);
0176
0177   if (update && gSystem->AccessPathName(path, kFileExists)) {
0178     update = kFALSE;
0179     create = kTRUE;
0180   }
0181
0182   assert(read || update || create);
0183
0184   int openFlags = IOFlags::OpenRead;
0185   if (!read)
0186     openFlags |= IOFlags::OpenWrite;
0187   if (create)
0188     openFlags |= IOFlags::OpenCreate;
0189   //if (recreate) openFlags |= IOFlags::OpenCreate | IOFlags::OpenTruncate;
0190   if (readwrap)
0191     openFlags |= IOFlags::OpenWrap;
0192
0193   // Open storage
0194   if (!(storage_ = StorageFactory::get()->open(path, openFlags))) {
0195     MakeZombie();
0196     gDirectory = gROOT;
0197     throw cms::Exception("TStorageFactoryFile::TStorageFactoryFile()") << "Cannot open file '" << path << "'";
0198   }
0199
0200   // Record the statistics.
0201   try {
0202     edm::Service<edm::storage::StatisticsSenderService> statsService;
0203     if (statsService.isAvailable()) {
0204       statsService->setSize(path, storage_->size());
0205     }
0206   } catch (edm::Exception const &e) {
0207     if (e.categoryCode() != edm::errors::NotFound) {
0208       throw;
0209     }
0210   }
0211
0212   fRealName = path;
0213   fD = 0;  // sorry, meaningless
0214   fWritable = read ? kFALSE : kTRUE;
0215
0216   Init(create);
0217
0218   stats.tick(0);
0219 }
0220
0221 TStorageFactoryFile::~TStorageFactoryFile(void) { Close(); }
0222
0223 //////////////////////////////////////////////////////////////////////
0224 //////////////////////////////////////////////////////////////////////
0225 //////////////////////////////////////////////////////////////////////
0226
0227 Bool_t TStorageFactoryFile::ReadBuffer(char *buf, Long64_t pos, Int_t len) {
0228   // This function needs to be optimized to minimize seeks.
0229   // See TFile::ReadBuffer(char *buf, Long64_t pos, Int_t len) in ROOT 5.27.06.
0230   Seek(pos);
0231   return ReadBuffer(buf, len);
0232 }
0233
0234 Bool_t TStorageFactoryFile::ReadBuffer(char *buf, Int_t len) {
0235   // Check that it's valid to access this file.
0236   if (IsZombie()) {
0237     Error("ReadBuffer", "Cannot read from a zombie file");
0238     return kTRUE;
0239   }
0240
0241   if (!IsOpen()) {
0242     Error("ReadBuffer", "Cannot read from a file that is not open");
0243     return kTRUE;
0244   }
0245
0246   // Read specified byte range from the storage.  Returns kTRUE in
0247   // case of error.  Note that ROOT uses this function recursively
0248   // to fill the cache; we use a flag to make sure our accounting
0249   // is reflected in a comprehensible manner.  The "read" counter
0250   // will include both, "readc" indicates how much read from the
0251   // cache, "readu" indicates how much we failed to read from the
0252   // cache (excluding those recursive reads), and "readx" counts
0253   // the amount actually passed to read from the storage object.
0254   StorageAccount::Stamp stats(storageCounter(s_statsRead, StorageAccount::Operation::read));
0255
0256   // If we have a cache, read from there first.  This returns 0
0257   // if the block hasn't been prefetched, 1 if it was in cache,
0258   // and 2 if there was an error.
0259   if (TFileCacheRead *c = GetCacheRead()) {
0260     Long64_t here = GetRelOffset();
0261     Bool_t async = c->IsAsyncReading();
0262
0263     StorageAccount::Stamp cstats(async
0264                                      ? storageCounter(s_statsCPrefetch, StorageAccount::Operation::readPrefetchToCache)
0265                                      : storageCounter(s_statsCRead, StorageAccount::Operation::readViaCache));
0266
0267     Int_t st = ReadBufferViaCache(async ? nullptr : buf, len);
0268
0269     if (st == 2) {
0270       Error("ReadBuffer",
0271             "ReadBufferViaCache failed. Asked to read nBytes: %d from offset: %lld with file size: %lld",
0272             len,
0273             here,
0274             GetSize());
0275       return kTRUE;
0276     }
0277
0278     if (st == 1) {
0279       if (async) {
0280         cstats.tick(len);
0281         Seek(here);
0282       } else {
0283         cstats.tick(len);
0284         stats.tick(len);
0285         return kFALSE;
0286       }
0287     }
0288   }
0289
0290   // FIXME: Re-enable read-ahead if the data wasn't in cache.
0291   // if (! st) storage_->caching(true, -1, s_readahead);
0292
0293   // A real read
0294   StorageAccount::Stamp xstats(storageCounter(s_statsXRead, StorageAccount::Operation::readActual));
0295   IOSize n = storage_->xread(buf, len);
0296   xstats.tick(n);
0297   stats.tick(n);
0298   if (n < static_cast<IOSize>(len)) {
0299     Error("ReadBuffer",
0300           "read from Storage::xread returned %ld. Asked to read n bytes: %d from offset: %lld with file size: %lld",
0301           n,
0302           len,
0303           GetRelOffset(),
0304           GetSize());
0305   }
0306   return n ? kFALSE : kTRUE;
0307 }
0308
0309 Bool_t TStorageFactoryFile::ReadBufferAsync(Long64_t off, Int_t len) {
0310   // Check that it's valid to access this file.
0311   if (IsZombie()) {
0312     Error("ReadBufferAsync", "Cannot read from a zombie file");
0313     return kTRUE;
0314   }
0315
0316   if (!IsOpen()) {
0317     Error("ReadBufferAsync", "Cannot read from a file that is not open");
0318     return kTRUE;
0319   }
0320
0321   StorageAccount::Stamp stats(storageCounter(s_statsARead, StorageAccount::Operation::readAsync));
0322
0323   // If asynchronous reading is disabled, bail out now, regardless
0324   // whether the underlying storage supports prefetching.  If it is
0325   // forced on, pretend it's on, even if the storage doesn't support
0326   // it, as this turns off the caching in ROOT's side.
0327   const StorageFactory *f = StorageFactory::get();
0328
0329   // Verify that we never using async reads in app-only mode
0330   if (f->cacheHint() == StorageFactory::CACHE_HINT_APPLICATION)
0331     return kTRUE;
0332
0333   // Let the I/O method indicate if it can do client-side prefetch.
0334   // If it does, then for example TTreeCache will drop its own cache
0335   // and will use the client-side cache of the actual I/O layer.
0336   // If len is zero ROOT is probing for prefetch support.
0337   if (len) {
0338     // FIXME: Synchronise caching.
0339     // storage_->caching(true, -1, 0);
0340     ;
0341   }
0342
0343   IOPosBuffer iov(off, (void *)nullptr, len ? len : PREFETCH_PROBE_LENGTH);
0344   if (storage_->prefetch(&iov, 1)) {
0345     stats.tick(len);
0346     return kFALSE;
0347   }
0348
0349   // Always ask ROOT to use async reads in storage-only mode,
0350   // regardless of whether the storage system supports it.
0351   if (f->cacheHint() == StorageFactory::CACHE_HINT_STORAGE)
0352     return kFALSE;
0353
0354   // Prefetching not available right now.
0355   return kTRUE;
0356 }
0357
0358 Bool_t TStorageFactoryFile::ReadBuffersSync(char *buf, Long64_t *pos, Int_t *len, Int_t nbuf) {
0359   /** Most storage systems are not prepared for the onslaught of small reads
0360    *  that ROOT will perform, even if they implement a vectored read interface.
0361    *
0362    *  Typically, on the server side, the loop is unrolled and the reads are
0363    *  issued sequentially - giving the OS no hint that you're about to read
0364    *  a very close-by byte in the near future.  Normally, OS read-ahead takes
0365    *  care of such situations; because the storage server has so many clients,
0366    *  and ROOT reads look random to the OS, the read-ahead becomes disabled.
0367    *
0368    *  Hence, this function will repack the application-layer request into an
0369    *  optimized storage-layer request.  The resulting request to the storage
0370    *  layer typically has a slightly larger number of bytes, but far less
0371    *  individual reads.
0372    *
0373    *  On average, the server's disks see a smaller number of overall reads,
0374    *  the number of bytes transferred over the network increases modestly
0375    *  (around 10%), and the single application request becomes one-to-two
0376    *  I/O transactions.  A clear win for all cases except high-latency WAN.
0377    */
0378
0379   Int_t remaining = nbuf;  // Number of read requests left to process.
0380   Int_t pack_count;        // Number of read requests processed by this iteration.
0381
0382   IOSize remaining_buffer_size = 0;
0383   // Calculate the remaining buffer size for the ROOT-owned buffer by adding
0384   // the size of the various requests.
0385   for (Int_t i = 0; i < nbuf; i++)
0386     remaining_buffer_size += len[i];
0387
0388   char *current_buffer = buf;
0389   Long64_t *current_pos = pos;
0390   Int_t *current_len = len;
0391
0392   ReadRepacker repacker;
0393
0394   while (remaining > 0) {
0395     pack_count = repacker.pack(
0396         static_cast<long long int *>(current_pos), current_len, remaining, current_buffer, remaining_buffer_size);
0397
0398     int real_bytes_processed = repacker.realBytesProcessed();
0399     IOSize io_buffer_used = repacker.bufferUsed();
0400
0401     // Issue readv, then unpack buffers.
0402     StorageAccount::Stamp xstats(storageCounter(s_statsXRead, StorageAccount::Operation::readActual));
0403     std::vector<IOPosBuffer> &iov = repacker.iov();
0404     IOSize result = storage_->readv(&iov[0], iov.size());
0405     if (result != io_buffer_used) {
0406       Error(
0407           "ReadBuffersSync", "Storage::readv returned different size result=%ld expected=%ld", result, io_buffer_used);
0408       return kTRUE;
0409     }
0410     xstats.tick(io_buffer_used);
0411     repacker.unpack(current_buffer);
0412
0413     // Update the location of the unused part of the input buffer.
0414     remaining_buffer_size -= real_bytes_processed;
0415     current_buffer += real_bytes_processed;
0416
0417     current_pos += pack_count;
0418     current_len += pack_count;
0419     remaining -= pack_count;
0420   }
0421   assert(remaining_buffer_size == 0);
0422   return kFALSE;
0423 }
0424
0425 Bool_t TStorageFactoryFile::ReadBuffers(char *buf, Long64_t *pos, Int_t *len, Int_t nbuf) {
0426   // Check that it's valid to access this file.
0427   if (IsZombie()) {
0428     Error("ReadBuffers", "Cannot read from a zombie file");
0429     return kTRUE;
0430   }
0431
0432   if (!IsOpen()) {
0433     Error("ReadBuffers", "Cannot read from a file that is not open");
0434     return kTRUE;
0435   }
0436
0437   // For synchronous reads, we have special logic to optimize the I/O requests
0438   // from ROOT before handing it to the storage.
0439   if (buf) {
0440     return ReadBuffersSync(buf, pos, len, nbuf);
0441   }
0442   // For an async read, we assume the storage system is smart enough to do the
0443   // optimization itself.
0444
0445   // Read from underlying storage.
0446   void *const nobuf = nullptr;
0447   Int_t total = 0;
0448   std::vector<IOPosBuffer> iov;
0449   iov.reserve(nbuf);
0450   for (Int_t i = 0; i < nbuf; ++i) {
0451     iov.emplace_back(pos[i], nobuf, len[i]);
0452     total += len[i];
0453   }
0454
0455   // Null buffer means asynchronous reads into I/O system's cache.
0456   bool success;
0457   StorageAccount::Stamp astats(storageCounter(s_statsARead, StorageAccount::Operation::readAsync));
0458   // Synchronise low-level cache with the supposed cache in TFile.
0459   // storage_->caching(true, -1, 0);
0460   success = storage_->prefetch(iov.data(), nbuf);
0461   astats.tick(total);
0462
0463   // If it didn't suceeed, pass down to the base class.
0464   if (not success) {
0465     if (TFile::ReadBuffers(buf, pos, len, nbuf)) {
0466       Error("ReadBuffers", "call to TFile::ReadBuffers failed after prefetch already failed.");
0467       return kTRUE;
0468     }
0469   }
0470   return kFALSE;
0471 }
0472
0473 Bool_t TStorageFactoryFile::WriteBuffer(const char *buf, Int_t len) {
0474   // Check that it's valid to access this file.
0475   if (IsZombie()) {
0476     Error("WriteBuffer", "Cannot write to a zombie file");
0477     return kTRUE;
0478   }
0479
0480   if (!IsOpen()) {
0481     Error("WriteBuffer", "Cannot write to a file that is not open");
0482     return kTRUE;
0483   }
0484
0485   if (!fWritable) {
0486     Error("WriteBuffer", "File is not writable");
0487     return kTRUE;
0488   }
0489
0490   StorageAccount::Stamp stats(storageCounter(s_statsWrite, StorageAccount::Operation::write));
0491   StorageAccount::Stamp cstats(storageCounter(s_statsCWrite, StorageAccount::Operation::writeViaCache));
0492
0493   // Try first writing via a cache, and if that's not possible, directly.
0494   Int_t st;
0495   switch ((st = WriteBufferViaCache(buf, len))) {
0496     case 0:
0497       // Actual write.
0498       {
0499         StorageAccount::Stamp xstats(storageCounter(s_statsXWrite, StorageAccount::Operation::writeActual));
0500         IOSize n = storage_->xwrite(buf, len);
0501         xstats.tick(n);
0502         stats.tick(n);
0503
0504         // FIXME: What if it's a short write?
0505         return n > 0 ? kFALSE : kTRUE;
0506       }
0507
0508     case 1:
0509       cstats.tick(len);
0510       stats.tick(len);
0511       return kFALSE;
0512
0513     case 2:
0514     default:
0515       Error("WriteBuffer", "Error writing to cache");
0516       return kTRUE;
0517   }
0518 }
0519
0520 //////////////////////////////////////////////////////////////////////
0521 //////////////////////////////////////////////////////////////////////
0522 //////////////////////////////////////////////////////////////////////
0523 // FIXME: Override GetBytesToPrefetch() so XROOTD can suggest how
0524 // large a prefetch cache to use.
0525 // FIXME: Asynchronous open support?
0526
0527 //////////////////////////////////////////////////////////////////////
0528 //////////////////////////////////////////////////////////////////////
0529 //////////////////////////////////////////////////////////////////////
0530 Int_t TStorageFactoryFile::SysOpen(const char *pathname, Int_t flags, UInt_t /* mode */) {
0531   StorageAccount::Stamp stats(storageCounter(s_statsOpen, StorageAccount::Operation::open));
0532
0533   if (storage_) {
0534     storage_->close();
0535   }
0536
0537   int openFlags = IOFlags::OpenRead;
0538   if (flags & O_WRONLY)
0539     openFlags = IOFlags::OpenWrite;
0540   else if (flags & O_RDWR)
0541     openFlags |= IOFlags::OpenWrite;
0542   if (flags & O_CREAT)
0543     openFlags |= IOFlags::OpenCreate;
0544   if (flags & O_APPEND)
0545     openFlags |= IOFlags::OpenAppend;
0546   if (flags & O_EXCL)
0547     openFlags |= IOFlags::OpenExclusive;
0548   if (flags & O_TRUNC)
0549     openFlags |= IOFlags::OpenTruncate;
0550   if (flags & O_NONBLOCK)
0551     openFlags |= IOFlags::OpenNonBlock;
0552
0553   if (!(storage_ = StorageFactory::get()->open(pathname, openFlags))) {
0554     MakeZombie();
0555     gDirectory = gROOT;
0556     throw cms::Exception("TStorageFactoryFile::SysOpen()") << "Cannot open file '" << pathname << "'";
0557   }
0558
0559   stats.tick();
0560   return 0;
0561 }
0562
0563 Int_t TStorageFactoryFile::SysClose(Int_t /* fd */) {
0564   StorageAccount::Stamp stats(storageCounter(s_statsClose, StorageAccount::Operation::close));
0565
0566   if (storage_) {
0567     storage_->close();
0568     releaseStorage();
0569   }
0570
0571   stats.tick();
0572   return 0;
0573 }
0574
0575 Long64_t TStorageFactoryFile::SysSeek(Int_t /* fd */, Long64_t offset, Int_t whence) {
0576   StorageAccount::Stamp stats(storageCounter(s_statsSeek, StorageAccount::Operation::seek));
0577   Storage::Relative rel = (whence == SEEK_SET ? Storage::SET : whence == SEEK_CUR ? Storage::CURRENT : Storage::END);
0578
0579   offset = storage_->position(offset, rel);
0580   stats.tick();
0581   return offset;
0582 }
0583
0584 Int_t TStorageFactoryFile::SysSync(Int_t /* fd */) {
0585   StorageAccount::Stamp stats(storageCounter(s_statsFlush, StorageAccount::Operation::flush));
0586   storage_->flush();
0587   stats.tick();
0588   return 0;
0589 }
0590
0591 Int_t TStorageFactoryFile::SysStat(Int_t /* fd */, Long_t *id, Long64_t *size, Long_t *flags, Long_t *modtime) {
0592   StorageAccount::Stamp stats(storageCounter(s_statsStat, StorageAccount::Operation::stat));
0593   // FIXME: Most of this is unsupported or makes no sense with Storage
0594   *id = ::Hash(fRealName);
0595   *size = storage_->size();
0596   *flags = 0;
0597   *modtime = 0;
0598   stats.tick();
0599   return 0;
0600 }
0601
0602 void TStorageFactoryFile::ResetErrno(void) const { TSystem::ResetErrno(); }