NFS: Fix another OPEN_DOWNGRADE bug

trondmypd · amschuma-ntap · commit e547f2628327 · 2016-06-28T16:55:34.000-04:00
Olga Kornievskaia reports that the following test fails to trigger an OPEN_DOWNGRADE on the wire, and only triggers the final CLOSE. fd0 = open(foo, RDRW) -- should be open on the wire for "both" fd1 = open(foo, RDONLY) -- should be open on the wire for "read" close(fd0) -- should trigger an open_downgrade read(fd1) close(fd1) The issue is that we're missing a check for whether or not the current state transitioned from an O_RDWR state as opposed to having transitioned from a combination of O_RDONLY and O_WRONLY. Reported-by: Olga Kornievskaia <aglo@umich.edu> Fixes: cd9288f ("NFSv4: Fix another bug in the close/open_downgrade code") Cc: stable@vger.kernel.org # 2.6.33+ Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
@@ -2882,12 +2882,11 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
 			call_close |= is_wronly;
 		else if (is_wronly)
 			calldata->arg.fmode |= FMODE_WRITE;
+		if (calldata->arg.fmode != (FMODE_READ|FMODE_WRITE))
+			call_close |= is_rdwr;
 	} else if (is_rdwr)
 		calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;
 
-	if (calldata->arg.fmode == 0)
-		call_close |= is_rdwr;
-
 	if (!nfs4_valid_open_stateid(state))
 		call_close = 0;
 	spin_unlock(&state->owner->so_lock);
