diff options
Diffstat (limited to 'mysys/my_sync.c')
| -rw-r--r-- | mysys/my_sync.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/mysys/my_sync.c b/mysys/my_sync.c new file mode 100644 index 00000000..6f8760c3 --- /dev/null +++ b/mysys/my_sync.c @@ -0,0 +1,188 @@ +/* + Copyright (c) 2003, 2011, Oracle and/or its affiliates + + 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 + the Free Software Foundation; version 2 of the License. + + 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */ + +#include "mysys_priv.h" +#include "mysys_err.h" +#include <errno.h> + + +ulong my_sync_count; /* Count number of sync calls */ + +static void (*before_sync_wait)(void)= 0; +static void (*after_sync_wait)(void)= 0; + +void thr_set_sync_wait_callback(void (*before_wait)(void), + void (*after_wait)(void)) +{ + before_sync_wait= before_wait; + after_sync_wait= after_wait; +} + +/* + Sync data in file to disk + + SYNOPSIS + my_sync() + fd File descritor to sync + my_flags Flags (now only MY_WME is supported) + + NOTE + 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) + + 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: %lu", fd, my_flags)); + + if (my_disable_sync) + DBUG_RETURN(0); + + statistic_increment(my_sync_count,&THR_LOCK_open); + + if (before_sync_wait) + (*before_sync_wait)(); + + do + { +#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 +#if defined(HAVE_FDATASYNC) && HAVE_DECL_FDATASYNC + res= fdatasync(fd); +#elif defined(HAVE_FSYNC) + res= fsync(fd); + if (res == -1 && errno == ENOLCK) + res= 0; /* Result Bug in Old FreeBSD */ +#elif defined(_WIN32) + res= my_win_fsync(fd); +#else +#error Cannot find a way to sync a file, durability in danger + res= 0; /* No sync (strange OS) */ +#endif + } while (res == -1 && errno == EINTR); + + if (res) + { + int er= errno; + if (!(my_errno= er)) + my_errno= -1; /* Unknown error */ + if (after_sync_wait) + (*after_sync_wait)(); + if ((my_flags & MY_IGNORE_BADFD) && + (er == EBADF || er == EINVAL || er == EROFS)) + { + DBUG_PRINT("info", ("ignoring errno %d", er)); + res= 0; + } + else if (my_flags & MY_WME) + my_error(EE_SYNC, MYF(ME_BELL), my_filename(fd), my_errno); + } + else + { + if (after_sync_wait) + (*after_sync_wait)(); + } + DBUG_RETURN(res); +} /* my_sync */ + + +/* + 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 __attribute__((unused)), + myf my_flags __attribute__((unused))) +{ +#ifdef NEED_EXPLICIT_SYNC_DIR + static const char cur_dir_name[]= {FN_CURLIB, 0}; + File dir_fd; + int res= 0; + const char *correct_dir_name; + DBUG_ENTER("my_sync_dir"); + DBUG_PRINT("my",("Dir: '%s' my_flags: %lu", dir_name, my_flags)); + /* 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 __attribute__((unused)), + myf my_flags __attribute__((unused))) +{ +#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 & ~MY_NOSYMLINKS); +#else + return 0; +#endif +} |