From 438386853d4c0c48fe73bf05a7d61c70ca5a3bfb Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Mon, 7 Sep 2015 15:46:24 +0800
Subject: [PATCH] ceph: improve readahead for file holes

When readahead encounters file holes, osd reply returns error -ENOENT,
finish_read() skips adding pages to the the page cache. So readahead
does not work for file holes. The fix is adding zero pages to the
page cache when -ENOENT is returned.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
---
 fs/ceph/addr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 98933350331c4..6471e28e0586b 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -276,7 +276,7 @@ static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
 	for (i = 0; i < num_pages; i++) {
 		struct page *page = osd_data->pages[i];
 
-		if (rc < 0)
+		if (rc < 0 && rc != ENOENT)
 			goto unlock;
 		if (bytes < (int)PAGE_CACHE_SIZE) {
 			/* zero (remainder of) page */
-- 
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