erts: rewrite efile_writev to handle partial writes correctly

2 files changed, 7 insertions, 3 deletions

diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c
index b132991a3b..36ed108b76 100644
--- a/erts/emulator/drivers/common/efile_drv.c
+++ b/erts/emulator/drivers/common/efile_drv.c
@@ -1385,7 +1385,11 @@ static void invoke_writev(void *data) {
 	size = d->c.writev.size;
     }
 
-    /* Copy the io vector to avoid locking the port que while writing */
+    /* Copy the io vector to avoid locking the port que while writing,
+     * also, both we and efile_writev might/will change the SysIOVec
+     * when segmenting or due to partial write and we do not want to
+     * tamper with the actual queue that we get from driver_peekq
+     */
     MUTEX_LOCK(d->c.writev.q_mtx); /* Lock before accessing the port queue */
     iov0 = driver_peekq(d->c.writev.port, &iovlen);
 
@@ -1424,7 +1428,7 @@ static void invoke_writev(void *data) {
 	} else {
 	    d->result_ok = efile_writev(&d->errInfo, 
 					d->flags, (int) d->fd,
-					iov, iovcnt, size);
+					iov, iovcnt);
 	}
     } else if (iovlen == 0) {
 	d->result_ok = 1;
diff --git a/erts/emulator/drivers/common/erl_efile.h b/erts/emulator/drivers/common/erl_efile.h
index 3868b38137..69ad02633c 100644
--- a/erts/emulator/drivers/common/erl_efile.h
+++ b/erts/emulator/drivers/common/erl_efile.h
@@ -162,7 +162,7 @@ int efile_write_info(Efile_error* errInfo, Efile_info* pInfo, char *name);
 int efile_write(Efile_error* errInfo, int flags, int fd, 
 		char* buf, size_t count);
 int efile_writev(Efile_error* errInfo, int flags, int fd, 
-		 SysIOVec* iov, int iovcnt, size_t size);
+		 SysIOVec* iov, int iovcnt);
 int efile_read(Efile_error* errInfo, int flags, int fd, 
 	       char* buf, size_t count, size_t* pBytesRead);
 int efile_seek(Efile_error* errInfo, int fd,