NFSv4: Ensure that we recover from the OPEN + OPEN_CONFIRM BAD_STATEID race
If the server is in the unconfirmed OPEN state for a given open owner
and receives a second OPEN for the same open owner, it will cancel the
state of the first request and set up an OPEN_CONFIRM for the second.
This can cause a race that is discussed in rfc3530 on page 181.
The following patch allows the client to recover by retrying the
original open request.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index a8be9af..ff37812 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -785,6 +785,16 @@
exception.retry = 1;
continue;
}
+ /*
+ * BAD_STATEID on OPEN means that the server cancelled our
+ * state before it received the OPEN_CONFIRM.
+ * Recover by retrying the request as per the discussion
+ * on Page 181 of RFC3530.
+ */
+ if (status == -NFS4ERR_BAD_STATEID) {
+ exception.retry = 1;
+ continue;
+ }
res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
status, &exception));
} while (exception.retry);