diff mbox series

[5.11,134/329] NFS: Only change the cookie verifier if the directory page cache is empty

Message ID 20210517140306.645842593@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH May 17, 2021, 2 p.m. UTC 
From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit f892c41c14e0fa3d78ce37de1d5c8161ed13bf08 ]

The cached NFSv3/v4 readdir cookies are associated with a verifier,
which is checked by the server on subsequent calls to readdir, and is
only expected to change when the cookies (and hence also the page cache
contents) are considered invalid.
We therefore do have to store the verifier, but only when the page cache
is empty.

Fixes: b593c09f83a2 ("NFS: Improve handling of directory verifiers")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/dir.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ca1dddc81436..d5f28a1f3671 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -928,7 +928,12 @@  static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
 			}
 			return res;
 		}
-		memcpy(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf));
+		/*
+		 * Set the cookie verifier if the page cache was empty
+		 */
+		if (desc->page_index == 0)
+			memcpy(nfsi->cookieverf, verf,
+			       sizeof(nfsi->cookieverf));
 	}
 	res = nfs_readdir_search_array(desc);
 	if (res == 0) {