postgres fsync

src/backend/utils/time/snapmgr.c:1336:  /* no fsync() since file need not survive a system crash */
src/backend/utils/init/miscinit.c:1196: if (pg_fsync(fd) != 0)
src/backend/utils/init/miscinit.c:1398: if (pg_fsync(fd) != 0)
src/backend/utils/misc/guc.c:1205:                      gettext_noop("The server will use the fsync() system call in several places to make "
src/backend/utils/misc/guc.c:8042:      if (pg_fsync(fd) != 0)
src/backend/utils/cache/relmapper.c:882:        if (pg_fsync(fd) != 0)
src/backend/access/transam/timeline.c:413:      if (pg_fsync(fd) != 0)
src/backend/access/transam/timeline.c:491:      if (pg_fsync(fd) != 0)
src/backend/access/transam/slru.c:892:          if (ctl->do_fsync && pg_fsync(fd) != 0)
src/backend/access/transam/slru.c:1183:         if (ctl->do_fsync && pg_fsync(fdata.fd[i]) != 0)
src/backend/access/transam/twophase.c:1664:     if (pg_fsync(fd) != 0)
src/backend/access/transam/xlog.c:2577:                         issue_xlog_fsync(openLogFile, openLogSegNo);
src/backend/access/transam/xlog.c:2648:                 issue_xlog_fsync(openLogFile, openLogSegNo);
src/backend/access/transam/xlog.c:3357: if (pg_fsync(fd) != 0)
src/backend/access/transam/xlog.c:3531: if (pg_fsync(fd) != 0)
src/backend/access/transam/xlog.c:4675: if (pg_fsync(fd) != 0)
src/backend/access/transam/xlog.c:5313: if (pg_fsync(openLogFile) != 0)
src/backend/access/transam/xlog.c:5407:                 (void) pg_fsync(fd);
src/backend/access/transam/xlog.c:5420:                 (void) pg_fsync(fd);
src/backend/access/transam/xlog.c:10308:                        if (pg_fsync(openLogFile) != 0)
src/backend/access/transam/xlog.c:10337:issue_xlog_fsync(int fd, XLogSegNo segno)
src/backend/access/transam/xlog.c:10806:                                pg_fsync(fileno(fp)) != 0 ||
src/backend/access/transam/xlog.c:10844:                                        pg_fsync(fileno(fp)) != 0 ||
src/backend/access/heap/rewriteheap.c:778: * deal with WAL logging at all - an fsync() at the end of a rewrite would be
src/backend/access/heap/rewriteheap.c:1172:     if (pg_fsync(fd) != 0)
src/backend/access/heap/rewriteheap.c:1275:                     if (pg_fsync(fd) != 0)
src/backend/storage/file/fd.c:156:/* Whether it is safe to continue running after fsync() fails. */
src/backend/storage/file/fd.c:343:pg_fsync(int fd)
src/backend/storage/file/fd.c:349:       * Some operating system implementations of fsync() have requirements
src/backend/storage/file/fd.c:354:       * For any file descriptor that may eventually be handed to fsync(), we
src/backend/storage/file/fd.c:356:       * fsync() on all supported systems, otherwise the code may not be
src/backend/storage/file/fd.c:363:       * Ignore any fstat errors and let the follow-up fsync() do its work.
src/backend/storage/file/fd.c:364:       * Doing this sanity check here counts for the case where fsync() is
src/backend/storage/file/fd.c:401:              return fsync(fd);
src/backend/storage/file/fd.c:440:              return fsync(fd);
src/backend/storage/file/fd.c:457:       * fsync()/fdatasync() calls have less impact. Thus don't trigger flushes
src/backend/storage/file/fd.c:683:              if (pg_fsync(fd) != 0)
src/backend/storage/file/fd.c:2139:     returnCode = pg_fsync(VfdCache[file].fd);
src/backend/storage/file/fd.c:3243: * Note that if we previously crashed due to a PANIC on fsync(), we'll be
src/backend/storage/file/fd.c:3293:      * Now we do the fsync()s in the same order.
src/backend/storage/file/fd.c:3380: * Hint to the OS that it should get ready to fsync() this file.
src/backend/storage/file/fd.c:3495:     returncode = pg_fsync(fd);
src/backend/storage/file/fd.c:3593: * Any code that reports a failure from fsync() or related functions should
src/backend/storage/smgr/md.c:907:       * may be some inactive segments left opened after fsync() error, but that
src/backend/replication/walreceiver.c:910:                       * fsync() and close current file before we switch to next one. We
src/backend/replication/walreceiver.c:1007:             issue_xlog_fsync(recvFile, recvSegNo);
src/backend/replication/logical/snapbuild.c:1630:        * It's safe to just ERROR on fsync() here because we'll retry the whole
src/backend/replication/logical/snapbuild.c:1633:        * TODO: Do the fsync() via checkpoints/restartpoints, doing it here has
src/backend/replication/logical/snapbuild.c:1638:       if (pg_fsync(fd) != 0)
src/backend/replication/logical/snapbuild.c:1718:        * slot without fsyncing, and saving it won't succeed without an fsync()
src/backend/replication/slot.c:584:              * We need to fsync() the directory we just renamed and its parent to
src/backend/replication/slot.c:586:              * fsync() fails, we can't be sure whether the changes are on disk or
src/backend/replication/slot.c:1406:    if (pg_fsync(fd) != 0)
src/backend/replication/slot.c:1506:     * place only after we fsync()ed the state file.
src/backend/replication/slot.c:1518:    if (pg_fsync(fd) != 0)
src/bin/pg_resetwal/pg_resetwal.c:1195: if (fsync(fd) != 0)
src/bin/pg_test_fsync/pg_test_fsync.c:3: *              tests all supported fsync() methods
src/bin/pg_test_fsync/pg_test_fsync.c:235:      if (fsync(tmpfile) != 0)
src/bin/pg_test_fsync/pg_test_fsync.c:324:              if (fsync(tmpfile) != 0)
src/bin/pg_test_fsync/pg_test_fsync.c:467:      printf(_("(If the times are similar, fsync() can sync data written on a different\n"
src/bin/pg_test_fsync/pg_test_fsync.c:484:              if (fsync(tmpfile) != 0)
src/bin/pg_test_fsync/pg_test_fsync.c:516:              if (fsync(tmpfile) != 0)
src/bin/pg_dump/pg_dump.c:91:static bool dosync = true;         /* Issue fsync() to make dump durable on disk. */
src/bin/pg_basebackup/pg_recvlogical.c:173:OutputFsync(TimestampTz now)
src/bin/pg_basebackup/pg_recvlogical.c:191:     if (fsync(outfd) != 0)
src/bin/pg_basebackup/pg_recvlogical.c:297:                     if (!OutputFsync(now))
src/bin/pg_basebackup/pg_recvlogical.c:316:                     if (!OutputFsync(now))
src/bin/pg_basebackup/pg_recvlogical.c:603:             OutputFsync(t);
src/bin/pg_basebackup/pg_recvlogical.c:999:     if (!OutputFsync(*now))
src/bin/pg_basebackup/walmethods.c:89:   * does not do any system calls to fsync() to make changes permanent on
src/bin/pg_basebackup/walmethods.c:298: return fsync(((DirectoryMethodFile *) f)->fd);
src/bin/pg_basebackup/walmethods.c:713: return fsync(tar_data->fd);
src/bin/pg_basebackup/walmethods.c:961:         if (fsync(tar_data->fd) != 0)
src/common/controldata_utils.c:236:             if (pg_fsync(fd) != 0)
src/common/controldata_utils.c:243:             if (fsync(fd) != 0)
src/common/file_utils.c:100:     * Now we do the fsync()s in the same order.
src/common/file_utils.c:206: * Hint to the OS that it should get ready to fsync() this file.
src/common/file_utils.c:287:    returncode = fsync(fd);
src/common/file_utils.c:363:            if (fsync(fd) != 0)