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authorFilipe David Manana <[email protected]>2010-04-22 23:40:26 +0100
committerRaimo Niskanen <[email protected]>2010-05-20 15:48:17 +0200
commit3f53a96a8bd0cd4a18f819b6857e6a764706ede5 (patch)
tree04841cd714a6e23ac664a05ff9219dd8e5da474e /erts/emulator/drivers/common
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/emulator/drivers/common')
-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
3 files changed, 32 insertions, 0 deletions
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);