[PATCH 3.16 124/125] NFSv4: Fix problems with close in the presence of a delegation

Greg Kroah-Hartman
2014-09-03T22:43:44Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

commit aee7af356e151494d5014f57b33460b162f181b5 upstream.

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...)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/nfs4proc.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2587,6 +2587,7 @@ static void nfs4_close_prepare(struct rp
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__);
@@ -2594,18 +2595,24 @@ static void nfs4_close_prepare(struct rp
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;
}
}