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NFSv41: Fix a potential state leakage when restarting nfs4_close_prepare
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Currently, if the call to nfs4_setup_sequence() in nfs4_close_prepare
fails, any later retries will fail to launch an RPC call, due to the fact
that the &state->flags will have been cleared.
Ditto if nfs4_close_done() triggers a call to the NFSv4.1 version of
nfs_restart_rpc().

We therefore move the actual clearing of the state->flags to
nfs4_close_done(), when we know that the RPC call was successful.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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Trond Myklebust authored and Trond Myklebust committed Dec 8, 2009
1 parent 74e7bb7 commit 88069f7
Showing 1 changed file with 35 additions and 17 deletions.
52 changes: 35 additions & 17 deletions fs/nfs/nfs4proc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -761,13 +761,16 @@ static int can_open_cached(struct nfs4_state *state, fmode_t mode, int open_mode
goto out;
switch (mode & (FMODE_READ|FMODE_WRITE)) {
case FMODE_READ:
ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0;
ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0
&& state->n_rdonly != 0;
break;
case FMODE_WRITE:
ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0;
ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0
&& state->n_wronly != 0;
break;
case FMODE_READ|FMODE_WRITE:
ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0;
ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0
&& state->n_rdwr != 0;
}
out:
return ret;
Expand Down Expand Up @@ -1711,6 +1714,18 @@ static void nfs4_free_closedata(void *data)
kfree(calldata);
}

static void nfs4_close_clear_stateid_flags(struct nfs4_state *state,
fmode_t fmode)
{
spin_lock(&state->owner->so_lock);
if (!(fmode & FMODE_READ))
clear_bit(NFS_O_RDONLY_STATE, &state->flags);
if (!(fmode & FMODE_WRITE))
clear_bit(NFS_O_WRONLY_STATE, &state->flags);
clear_bit(NFS_O_RDWR_STATE, &state->flags);
spin_unlock(&state->owner->so_lock);
}

static void nfs4_close_done(struct rpc_task *task, void *data)
{
struct nfs4_closedata *calldata = data;
Expand All @@ -1727,6 +1742,8 @@ static void nfs4_close_done(struct rpc_task *task, void *data)
case 0:
nfs_set_open_stateid(state, &calldata->res.stateid, 0);
renew_lease(server, calldata->timestamp);
nfs4_close_clear_stateid_flags(state,
calldata->arg.fmode);
break;
case -NFS4ERR_STALE_STATEID:
case -NFS4ERR_OLD_STATEID:
Expand All @@ -1747,38 +1764,39 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
{
struct nfs4_closedata *calldata = data;
struct nfs4_state *state = calldata->state;
int clear_rd, clear_wr, clear_rdwr;
int call_close = 0;

if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
return;

clear_rd = clear_wr = clear_rdwr = 0;
task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
calldata->arg.fmode = FMODE_READ|FMODE_WRITE;
spin_lock(&state->owner->so_lock);
/* Calculate the change in open mode */
if (state->n_rdwr == 0) {
if (state->n_rdonly == 0) {
clear_rd |= test_and_clear_bit(NFS_O_RDONLY_STATE, &state->flags);
clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
call_close |= test_bit(NFS_O_RDONLY_STATE, &state->flags);
call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
calldata->arg.fmode &= ~FMODE_READ;
}
if (state->n_wronly == 0) {
clear_wr |= test_and_clear_bit(NFS_O_WRONLY_STATE, &state->flags);
clear_rdwr |= test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags);
call_close |= test_bit(NFS_O_WRONLY_STATE, &state->flags);
call_close |= test_bit(NFS_O_RDWR_STATE, &state->flags);
calldata->arg.fmode &= ~FMODE_WRITE;
}
}
spin_unlock(&state->owner->so_lock);
if (!clear_rd && !clear_wr && !clear_rdwr) {

if (!call_close) {
/* Note: exit _without_ calling nfs4_close_done */
task->tk_action = NULL;
return;
}

if (calldata->arg.fmode == 0)
task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];

nfs_fattr_init(calldata->res.fattr);
if (test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0) {
task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
calldata->arg.fmode = FMODE_READ;
} else if (test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0) {
task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
calldata->arg.fmode = FMODE_WRITE;
}
calldata->timestamp = jiffies;
if (nfs4_setup_sequence((NFS_SERVER(calldata->inode))->nfs_client,
&calldata->arg.seq_args, &calldata->res.seq_res,
Expand Down

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