NFS: Fix another OPEN_DOWNGRADE bug

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: cd9288ffaea4 ("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
index 406dd3e..ff416d0 100644 (file)
--- 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);