LU-13470 ptlrpc: return proper write count from ping_store

If we return 0 as a measure of success, that is actually taken
by userspace as "we wrote 0 bytes, but there's no error, so
they want us to retry". So tell them we ate all their data
instead to make them happy.

Interesting that when you do shell-redirect it enters the
retry loop, but badarea_io does not.

Change-Id: Ieb0f8bcd4f010ab4375ea6f65f6ea00248a236cb
Signed-off-by: Oleg Drokin <green@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/38304
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lustre/ptlrpc/lproc_ptlrpc.c b/lustre/ptlrpc/lproc_ptlrpc.c
index 579a175..ce7d386 100644 (file)
--- a/lustre/ptlrpc/lproc_ptlrpc.c
+++ b/lustre/ptlrpc/lproc_ptlrpc.c
@@ -1330,7 +1330,9 @@ EXPORT_SYMBOL(ping_show);
 ssize_t ping_store(struct kobject *kobj, struct attribute *attr,
                   const char *buffer, size_t count)
 {
-       return ping_show(kobj, attr, (char *)buffer);
+       int rc = ping_show(kobj, attr, (char *)buffer);
+
+       return (rc < 0) ? rc : count;
 }
 EXPORT_SYMBOL(ping_store);