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authorFilipe David Manana <fdmanana@gmail.com>2010-04-22 23:40:26 +0100
committerRaimo Niskanen <raimo@erlang.org>2010-05-20 15:48:17 +0200
commit3f53a96a8bd0cd4a18f819b6857e6a764706ede5 (patch)
tree04841cd714a6e23ac664a05ff9219dd8e5da474e /erts
parent80b231a0874aa5cd68c3d9f0dc7e13b6736a5dd3 (diff)
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Add file:datasync/1 for syncing file contents only
file:datasync/1 invokes the POSIX system call "int fdatasync(int fd)". This system call is similar to "fsync" but, unlike fsync, it does not update the metadata associated with the file (like the access time for example). It's used by many DBMSs (MySQL and SQLite of example) to increase disk IO performance, as it avoids disk seeks and disk write operations compared to fsync. More details on it at: http://linux.die.net/man/2/fdatasync An example, from the MySQL source: http://bazaar.launchpad.net/~mysql/mysql-server/mysql-5.1-telco-6.1/annotate/head%3A/mysys/my_sync.c#L61 This new function just calls fsync on systems not implementing fdatasync.
Diffstat (limited to 'erts')
-rw-r--r--erts/configure.in6
-rw-r--r--erts/emulator/drivers/common/efile_drv.c23
-rw-r--r--erts/emulator/drivers/common/erl_efile.h1
-rw-r--r--erts/emulator/drivers/common/ram_file_drv.c8
-rw-r--r--erts/emulator/drivers/unix/unix_efile.c11
-rw-r--r--erts/emulator/drivers/win32/win_efile.c9
-rw-r--r--erts/preloaded/src/prim_file.erl6
7 files changed, 63 insertions, 1 deletions
diff --git a/erts/configure.in b/erts/configure.in
index a14b10adbf..f11aba1b15 100644
--- a/erts/configure.in
+++ b/erts/configure.in
@@ -1757,6 +1757,12 @@ fi
dnl Need by run_erl.
AC_CHECK_FUNCS([openpty])
+dnl fdatasync syscall (Unix only)
+AC_CHECK_FUNCS([fdatasync])
+
+dnl Find which C libraries are required to use fdatasync
+AC_SEARCH_LIBS(fdatasync, [rt])
+
dnl ----------------------------------------------------------------------
dnl Checks for features/quirks in the system that affects Erlang.
dnl ----------------------------------------------------------------------
diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c
index d2b916000e..b64d27de68 100644
--- a/erts/emulator/drivers/common/efile_drv.c
+++ b/erts/emulator/drivers/common/efile_drv.c
@@ -53,6 +53,7 @@
#define FILE_IPREAD 27
#define FILE_ALTNAME 28
#define FILE_READ_LINE 29
+#define FILE_FDATASYNC 30
/* Return codes */
@@ -883,6 +884,15 @@ static void invoke_chdir(void *data)
invoke_name(data, efile_chdir);
}
+static void invoke_fdatasync(void *data)
+{
+ struct t_data *d = (struct t_data *) data;
+ int fd = (int) d->fd;
+
+ d->again = 0;
+ d->result_ok = efile_fdatasync(&d->errInfo, fd);
+}
+
static void invoke_fsync(void *data)
{
struct t_data *d = (struct t_data *) data;
@@ -1919,6 +1929,7 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data)
case FILE_RMDIR:
case FILE_CHDIR:
case FILE_DELETE:
+ case FILE_FDATASYNC:
case FILE_FSYNC:
case FILE_TRUNCATE:
case FILE_LINK:
@@ -2209,6 +2220,18 @@ file_output(ErlDrvData e, char* buf, int count)
goto done;
}
+ case FILE_FDATASYNC:
+ {
+ d = EF_SAFE_ALLOC(sizeof(struct t_data));
+
+ d->fd = fd;
+ d->command = command;
+ d->invoke = invoke_fdatasync;
+ d->free = free_data;
+ d->level = 2;
+ goto done;
+ }
+
case FILE_FSYNC:
{
d = EF_SAFE_ALLOC(sizeof(struct t_data));
diff --git a/erts/emulator/drivers/common/erl_efile.h b/erts/emulator/drivers/common/erl_efile.h
index 9aa941e550..6821a0e2ee 100644
--- a/erts/emulator/drivers/common/erl_efile.h
+++ b/erts/emulator/drivers/common/erl_efile.h
@@ -126,6 +126,7 @@ int efile_readdir(Efile_error* errInfo, char* name,
int efile_openfile(Efile_error* errInfo, char* name, int flags,
int* pfd, Sint64* pSize);
void efile_closefile(int fd);
+int efile_fdatasync(Efile_error* errInfo, int fd);
int efile_fsync(Efile_error* errInfo, int fd);
int efile_fileinfo(Efile_error* errInfo, Efile_info* pInfo,
char *name, int info_for_link);
diff --git a/erts/emulator/drivers/common/ram_file_drv.c b/erts/emulator/drivers/common/ram_file_drv.c
index 4a39a156e6..d4e547ade6 100644
--- a/erts/emulator/drivers/common/ram_file_drv.c
+++ b/erts/emulator/drivers/common/ram_file_drv.c
@@ -35,6 +35,7 @@
#define RAM_FILE_TRUNCATE 14
#define RAM_FILE_PREAD 17
#define RAM_FILE_PWRITE 18
+#define RAM_FILE_FDATASYNC 19
/* other operations */
#define RAM_FILE_GET 30
@@ -558,6 +559,13 @@ static void rfile_command(ErlDrvData e, char* buf, int count)
numeric_reply(f, 0); /* 0 is not used */
break;
+ case RAM_FILE_FDATASYNC:
+ if (f->flags == 0)
+ error_reply(f, EBADF);
+ else
+ reply(f, 1, 0);
+ break;
+
case RAM_FILE_FSYNC:
if (f->flags == 0)
error_reply(f, EBADF);
diff --git a/erts/emulator/drivers/unix/unix_efile.c b/erts/emulator/drivers/unix/unix_efile.c
index 1d094ee613..0cece76221 100644
--- a/erts/emulator/drivers/unix/unix_efile.c
+++ b/erts/emulator/drivers/unix/unix_efile.c
@@ -774,6 +774,17 @@ efile_closefile(int fd)
}
int
+efile_fdatasync(Efile_error *errInfo, /* Where to return error codes. */
+ int fd) /* File descriptor for file to sync data. */
+{
+#ifdef HAVE_FDATASYNC
+ return check_error(fdatasync(fd), errInfo);
+#else
+ return efile_fsync(errInfo, fd);
+#endif
+}
+
+int
efile_fsync(Efile_error *errInfo, /* Where to return error codes. */
int fd) /* File descriptor for file to sync. */
{
diff --git a/erts/emulator/drivers/win32/win_efile.c b/erts/emulator/drivers/win32/win_efile.c
index 89aaad31da..cdf3bb424c 100644
--- a/erts/emulator/drivers/win32/win_efile.c
+++ b/erts/emulator/drivers/win32/win_efile.c
@@ -764,6 +764,15 @@ int fd; /* File descriptor for file to close. */
}
int
+efile_fdatasync(errInfo, fd)
+Efile_error* errInfo; /* Where to return error codes. */
+int fd; /* File descriptor for file to sync. */
+{
+ /* Not available in Windows, just call regular fsync */
+ return efile_fsync(errInfo, fd);
+}
+
+int
efile_fsync(errInfo, fd)
Efile_error* errInfo; /* Where to return error codes. */
int fd; /* File descriptor for file to sync. */
diff --git a/erts/preloaded/src/prim_file.erl b/erts/preloaded/src/prim_file.erl
index 43e6f6cd88..53c741e66e 100644
--- a/erts/preloaded/src/prim_file.erl
+++ b/erts/preloaded/src/prim_file.erl
@@ -25,7 +25,7 @@
%%% Interface towards a single file's contents. Uses ?FD_DRV.
%% Generic file contents operations
--export([open/2, close/1, sync/1, position/2, truncate/1,
+-export([open/2, close/1, datasync/1, sync/1, position/2, truncate/1,
write/2, pwrite/2, pwrite/3, read/2, read_line/1, pread/2, pread/3, copy/3]).
%% Specialized file operations
@@ -96,6 +96,7 @@
-define(FILE_IPREAD, 27).
-define(FILE_ALTNAME, 28).
-define(FILE_READ_LINE, 29).
+-define(FILE_FDATASYNC, 30).
%% Driver responses
-define(FILE_RESP_OK, 0).
@@ -292,6 +293,9 @@ pwrite(#file_descriptor{module = ?MODULE}, _, _) ->
{error, badarg}.
+%% Returns {error, Reason} | ok.
+datasync(#file_descriptor{module = ?MODULE, data = {Port, _}}) ->
+ drv_command(Port, [?FILE_FDATASYNC]).
%% Returns {error, Reason} | ok.
sync(#file_descriptor{module = ?MODULE, data = {Port, _}}) ->