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a41ac15b96
1) on Mac OS X >=10.3, fcntl() is recommended over fsync (from the man page: "[With fsync()] the disk drive may also re-order the data so that later writes may be present while earlier writes are not. Applications such as databases that require a strict ordering of writes should use F_FULLFSYNC to ensure their data is written in the order they expect"). I have seen two other pieces of software changing from fsync to F_FULLFSYNC on Mac OS X. 2) to make a file creation/deletion/renaming durable on Linux (at least ext2 as I have tested) (see "man fsync"), a fsync() on the directory is needed: new functions to do that, and a flag MY_SYNC_DIR to do it in my_create/my_delete/my_rename. 3) now using this directory syncing when creating he frm if opt_sync_frm, and for Maria's control file when it is created. include/my_sys.h: new flag to my_create/my_delete/my_rename, which asks to sync the directory after the operation is done (currently does nothing except on Linux) libmysql/CMakeLists.txt: my_create() now depends on my_sync() so my_sync is needed for libmysql libmysql/Makefile.shared: my_create() now depends on my_sync() so my_sync is needed for libmysql mysys/my_create.c: my_create() can now sync the directory if asked for mysys/my_delete.c: my_delete() can now sync the directory if asked for mysys/my_open.c: it was a bug that my_close() is done on fd but a positive fd would still be returned, by my_register_filename(). mysys/my_rename.c: my_rename() can now sync the two directories (the one of "from" and the one of "to") if asked for. mysys/my_sync.c: On recent Mac OS X, fcntl(F_FULLFSYNC) is recommended over fsync() (see "man fsync" on Mac OS X 10.3). my_sync_dir(): to sync a directory after a file creation/deletion/ renaming; can be called directly or via MY_SYNC_DIR in my_create/ my_delete/my_rename(). No-op except on Linux (see "man fsync" on Linux). my_sync_dir_from_file(): same as above, just more practical when the caller has a file name but no directory name ready. Should the #warning even be a #error? I mean do we want to release binaries which don't guarantee any durability? sql/log.cc: a TODO for the future. sql/unireg.cc: If we sync the frm it makes sense to also sync its creation in the directory. storage/maria/ma_control_file.c: control file is vital, try to make it to disk
150 lines
4.1 KiB
C
150 lines
4.1 KiB
C
/* Copyright (C) 2003 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "mysys_priv.h"
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#include "mysys_err.h"
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#include <errno.h>
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/*
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Sync data in file to disk
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SYNOPSIS
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my_sync()
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fd File descritor to sync
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my_flags Flags (now only MY_WME is supported)
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NOTE
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If file system supports its, only file data is synced, not inode data.
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MY_IGNORE_BADFD is useful when fd is "volatile" - not protected by a
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mutex. In this case by the time of fsync(), fd may be already closed by
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another thread, or even reassigned to a different file. With this flag -
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MY_IGNORE_BADFD - such a situation will not be considered an error.
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(which is correct behaviour, if we know that the other thread synced the
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file before closing)
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RETURN
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0 ok
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-1 error
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*/
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int my_sync(File fd, myf my_flags)
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{
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int res;
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DBUG_ENTER("my_sync");
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DBUG_PRINT("my",("Fd: %d my_flags: %d", fd, my_flags));
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do
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{
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#if defined(F_FULLFSYNC)
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/* Recent Mac OS X versions insist this call is safer than fsync() */
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if (!(res= fcntl(fd, F_FULLFSYNC, 0)))
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break; /* ok */
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/* Some fs don't support F_FULLFSYNC and fail above, fallback: */
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#endif
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#if defined(HAVE_FDATASYNC)
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res= fdatasync(fd);
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#elif defined(HAVE_FSYNC)
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res= fsync(fd);
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#elif defined(__WIN__)
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res= _commit(fd);
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#else
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#warning Cannot find a way to sync a file, durability in danger
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res= 0; /* No sync (strange OS) */
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#endif
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} while (res == -1 && errno == EINTR);
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if (res)
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{
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int er= errno;
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if (!(my_errno= er))
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my_errno= -1; /* Unknown error */
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if ((my_flags & MY_IGNORE_BADFD) &&
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(er == EBADF || er == EINVAL || er == EROFS))
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res= 0;
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else if (my_flags & MY_WME)
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my_error(EE_SYNC, MYF(ME_BELL+ME_WAITTANG), my_filename(fd), my_errno);
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}
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DBUG_RETURN(res);
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} /* my_sync */
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/*
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Force directory information to disk. Only Linux is known to need this to
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make sure a file creation/deletion/renaming in(from,to) this directory
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durable.
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SYNOPSIS
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my_sync_dir()
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dir_name the name of the directory
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my_flags unused
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RETURN
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nothing (the sync may fail sometimes).
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*/
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void my_sync_dir(const char *dir_name, myf my_flags __attribute__((unused)))
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{
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#ifdef TARGET_OS_LINUX
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DBUG_ENTER("my_sync_dir");
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DBUG_PRINT("my",("Dir: '%s' my_flags: %d", dir_name, my_flags));
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File dir_fd;
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int error= 0;
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/*
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Syncing a dir does not work on all filesystems (e.g. tmpfs->EINVAL) :
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ignore errors. But print them to the debug log.
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*/
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if (((dir_fd= my_open(dir_name, O_RDONLY, MYF(0))) >= 0))
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{
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if (my_sync(dir_fd, MYF(0)))
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{
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error= errno;
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DBUG_PRINT("info",("my_sync failed errno: %d", error));
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}
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my_close(dir_fd, MYF(0));
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}
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else
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{
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error= errno;
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DBUG_PRINT("info",("my_open failed errno: %d", error));
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}
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DBUG_VOID_RETURN;
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#endif
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}
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/*
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Force directory information to disk. Only Linux is known to need this to
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make sure a file creation/deletion/renaming in(from,to) this directory
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durable.
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SYNOPSIS
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my_sync_dir_by_file()
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file_name the name of a file in the directory
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my_flags unused
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RETURN
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nothing (the sync may fail sometimes).
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*/
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void my_sync_dir_by_file(const char *file_name,
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myf my_flags __attribute__((unused)))
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{
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#ifdef TARGET_OS_LINUX
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char dir_name[FN_REFLEN];
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dirname_part(dir_name, file_name);
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return my_sync_dir(dir_name, my_flags);
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#endif
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}
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