NFSv4: Fix problems with close in the presence of a delegation

In the presence of delegations, we can no longer assume that the
state->n_rdwr, state->n_rdonly, state->n_wronly reflect the open
stateid share mode, and so we need to calculate the initial value
for calldata->arg.fmode using the state->flags.

Reported-by: James Drews <drews@engr.wisc.edu>
Fixes: 88069f77e1ac5 (NFSv41: Fix a potential state leakage when...)
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 75ae8d22f067..ff94a2f36051 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2601,6 +2601,7 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
         struct nfs4_closedata *calldata = data;
         struct nfs4_state *state = calldata->state;
         struct inode *inode = calldata->inode;
+        bool is_rdonly, is_wronly, is_rdwr;
         int call_close = 0;
 
         dprintk("%s: begin!\n", __func__);
@@ -2608,18 +2609,24 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
                 goto out_wait;
 
         task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
-        calldata->arg.fmode = FMODE_READ|FMODE_WRITE;
         spin_lock(&state->owner->so_lock);
+        is_rdwr = test_bit(NFS_O_RDWR_STATE, &state->flags);
+        is_rdonly = test_bit(NFS_O_RDONLY_STATE, &state->flags);
+        is_wronly = test_bit(NFS_O_WRONLY_STATE, &state->flags);
+        /* Calculate the current open share mode */
+        calldata->arg.fmode = 0;
+        if (is_rdonly || is_rdwr)
+                calldata->arg.fmode |= FMODE_READ;
+        if (is_wronly || is_rdwr)
+                calldata->arg.fmode |= FMODE_WRITE;
         /* Calculate the change in open mode */
         if (state->n_rdwr == 0) {
                 if (state->n_rdonly == 0) {
-                        call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
-                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+                        call_close |= is_rdonly || is_rdwr;
                         calldata->arg.fmode &= ~FMODE_READ;
                 }
                 if (state->n_wronly == 0) {
-                        call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
-                        call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
+                        call_close |= is_wronly || is_rdwr;
                         calldata->arg.fmode &= ~FMODE_WRITE;
                 }
         }