diff mbox series

NFS: Only change the cookie verifier if the directory page cache is empty

Message ID 20210317130110.1257066-1-trondmy@kernel.org (mailing list archive)
State New
Headers show
Series NFS: Only change the cookie verifier if the directory page cache is empty | expand

Commit Message

trondmy@kernel.org March 17, 2021, 1:01 p.m. UTC
From: Trond Myklebust <trond.myklebust@hammerspace.com>

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>
---
 fs/nfs/dir.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
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Patch

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 2cf2a7d92faf..0cd7c59a6601 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -929,7 +929,12 @@  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) {