my_sync.c 4.14 KB
Newer Older
1 2 3 4
/* Copyright (C) 2003 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
5
   the Free Software Foundation; version 2 of the License.
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "mysys_priv.h"
#include "mysys_err.h"
#include <errno.h>

/*
  Sync data in file to disk

  SYNOPSIS
    my_sync()
    fd			File descritor to sync
    my_flags		Flags (now only MY_WME is supported)

  NOTE
29 30 31 32 33 34 35 36
    If file system supports its, only file data is synced, not inode data.

    MY_IGNORE_BADFD is useful when fd is "volatile" - not protected by a
    mutex. In this case by the time of fsync(), fd may be already closed by
    another thread, or even reassigned to a different file. With this flag -
    MY_IGNORE_BADFD - such a situation will not be considered an error.
    (which is correct behaviour, if we know that the other thread synced the
    file before closing)
37 38 39 40 41 42 43 44 45 46 47 48

  RETURN
    0 ok
    -1 error
*/

int my_sync(File fd, myf my_flags)
{
  int res;
  DBUG_ENTER("my_sync");
  DBUG_PRINT("my",("Fd: %d  my_flags: %d", fd, my_flags));

49 50
  do
  {
51 52 53 54 55 56 57 58 59 60
#if defined(F_FULLFSYNC)
    /*
      In Mac OS X >= 10.3 this call is safer than fsync() (it forces the
      disk's cache and guarantees ordered writes).
    */
    if (!(res= fcntl(fd, F_FULLFSYNC, 0)))
      break; /* ok */
    /* Some file systems don't support F_FULLFSYNC and fail above: */
    DBUG_PRINT("info",("fcntl(F_FULLFSYNC) failed, falling back"));
#endif
61
#if defined(HAVE_FDATASYNC)
62
    res= fdatasync(fd);
63
#elif defined(HAVE_FSYNC)
64
    res= fsync(fd);
65 66 67
#elif defined(__WIN__)
    res= _commit(fd);
#else
68
#error Cannot find a way to sync a file, durability in danger
69
    res= 0;					/* No sync (strange OS) */
70
#endif
71 72
  } while (res == -1 && errno == EINTR);

73 74
  if (res)
  {
75 76 77
    int er= errno;
    if (!(my_errno= er))
      my_errno= -1;                             /* Unknown error */
78
    if ((my_flags & MY_IGNORE_BADFD) &&
79
        (er == EBADF || er == EINVAL || er == EROFS))
80 81
    {
      DBUG_PRINT("info", ("ignoring errno %d", er));
82
      res= 0;
83
    }
84
    else if (my_flags & MY_WME)
85 86 87
      my_error(EE_SYNC, MYF(ME_BELL+ME_WAITTANG), my_filename(fd), my_errno);
  }
  DBUG_RETURN(res);
88 89
} /* my_sync */

90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108

static const char cur_dir_name[]= {FN_CURLIB, 0};
/*
  Force directory information to disk.

  SYNOPSIS
    my_sync_dir()
    dir_name             the name of the directory
    my_flags             flags (MY_WME etc)

  RETURN
    0 if ok, !=0 if error
*/
int my_sync_dir(const char *dir_name, myf my_flags)
{
#ifdef NEED_EXPLICIT_SYNC_DIR
  File dir_fd;
  int res= 0;
  const char *correct_dir_name;
109 110
  DBUG_ENTER("my_sync_dir");
  DBUG_PRINT("my",("Dir: '%s'  my_flags: %d", dir_name, my_flags));
111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155
  /* Sometimes the path does not contain an explicit directory */
  correct_dir_name= (dir_name[0] == 0) ? cur_dir_name : dir_name;
  /*
    Syncing a dir may give EINVAL on tmpfs on Linux, which is ok.
    EIO on the other hand is very important. Hence MY_IGNORE_BADFD.
  */
  if ((dir_fd= my_open(correct_dir_name, O_RDONLY, MYF(my_flags))) >= 0)
  {
    if (my_sync(dir_fd, MYF(my_flags | MY_IGNORE_BADFD)))
      res= 2;
    if (my_close(dir_fd, MYF(my_flags)))
      res= 3;
  }
  else
    res= 1;
  DBUG_RETURN(res);
#else
  return 0;
#endif
}


/*
  Force directory information to disk.

  SYNOPSIS
    my_sync_dir_by_file()
    file_name            the name of a file in the directory
    my_flags             flags (MY_WME etc)

  RETURN
    0 if ok, !=0 if error
*/
int my_sync_dir_by_file(const char *file_name, myf my_flags)
{
#ifdef NEED_EXPLICIT_SYNC_DIR
  char dir_name[FN_REFLEN];
  size_t dir_name_length;
  dirname_part(dir_name, file_name, &dir_name_length);
  return my_sync_dir(dir_name, my_flags);
#else
  return 0;
#endif
}