From: Andrew Tridgell <tridge@samba.org>
Date: Fri, 19 Jun 1998 00:55:19 +0000 (+0000)
Subject: if we get EWOULDBLOCK on a write then reduce the amount of data we are
X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/commitdiff_plain/bf9f01689f9cba70ed595ddcfabdf92d4b03cb80

if we get EWOULDBLOCK on a write then reduce the amount of data we are
trying to write. This guarantees that the maximum amount of data that
can be written at any one time is written.
---

diff --git a/io.c b/io.c
index 7909e0b1..d7140d26 100644
--- a/io.c
+++ b/io.c
@@ -319,6 +319,7 @@ static void writefd_unbuffered(int fd,char *buf,int len)
 	int fd_count, count;
 	struct timeval tv;
 	int reading;
+	int blocked=0;
 
 	no_flush++;
 
@@ -350,7 +351,8 @@ static void writefd_unbuffered(int fd,char *buf,int len)
 		}
 
 		if (FD_ISSET(fd, &w_fds)) {
-			int ret = write(fd,buf+total,len-total);
+			int n = (len-total)>>blocked;
+			int ret = write(fd,buf+total,n?n:1);
 
 			if (ret == -1 && errno == EINTR) {
 				continue;
@@ -358,10 +360,7 @@ static void writefd_unbuffered(int fd,char *buf,int len)
 
 			if (ret == -1 && 
 			    (errno == EAGAIN || errno == EWOULDBLOCK)) {
-				/* this shouldn't happen, if it does then
-				   sleep for a short time to prevent us
-				   chewing too much CPU */
-				u_sleep(100);
+				blocked++;
 				continue;
 			}
 
@@ -370,6 +369,7 @@ static void writefd_unbuffered(int fd,char *buf,int len)
 				exit_cleanup(1);
 			}
 
+			blocked = 0;
 			total += ret;
 			stats.total_written += ret;