From: majianpeng <majianpeng@gmail.com>
Date: Wed, 21 Aug 2013 07:02:51 +0000 (+0800)
Subject: ceph: allow sync_read/write return partial successed size of read/write.
X-Git-Tag: firefly_0821_release~3679^2~3146
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=30379f4553bae684a928c6bdd9dc606fd0ef6093;p=firefly-linux-kernel-4.4.55.git

ceph: allow sync_read/write return partial successed size of read/write.

commit ee7289bfadda5f4ef60884547ebc9989c8fb314a upstream.

For sync_read/write, it may do multi stripe operations.If one of those
met erro, we return the former successed size rather than a error value.
There is a exception for write-operation met -EOLDSNAPC.If this occur,we
retry the whole write again.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 1ac0a59867dc..5de16f5ac7e9 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -373,7 +373,7 @@ more:
 			goto more;
 	}
 
-	if (ret >= 0) {
+	if (read > 0) {
 		ret = read;
 		/* did we bounce off eof? */
 		if (pos + left > inode->i_size)
@@ -611,6 +611,8 @@ out:
 		if (check_caps)
 			ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
 					NULL);
+	} else if (ret != -EOLDSNAPC && written > 0) {
+		ret = written;
 	}
 	return ret;
 }