[ 046/150] NFSv4.1: Fix an ABBA locking issue with session and state serialisation

Greg Kroah-Hartman
2013-02-27T01:08:00Z

From: Trond Myklebust <Trond.Myklebust@netapp.com>

commit c8da19b9866ea84e9ad1c369393ea95d54ee7845 upstream.

Ensure that if nfs_wait_on_sequence() causes our rpc task to wait for
an NFSv4 state serialisation lock, then we also drop the session slot.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/nfs4proc.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1463,7 +1463,7 @@ static void nfs4_open_prepare(struct rpc
struct nfs4_state_owner *sp = data->owner;

if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)
- return;
+ goto out_wait;
/*
* Check if we still need to send an OPEN call, or if we can use
* a delegation instead.
@@ -1498,6 +1498,7 @@ unlock_no_action:
rcu_read_unlock();
out_no_action:
task->tk_action = NULL;
+out_wait:
nfs4_sequence_done(task, &data->o_res.seq_res);
}

@@ -2150,7 +2151,7 @@ static void nfs4_close_prepare(struct rp

dprintk("%s: begin!\n", __func__);
if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
- return;
+ goto out_wait;

task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
calldata->arg.fmode = FMODE_READ|FMODE_WRITE;
@@ -2172,16 +2173,14 @@ static void nfs4_close_prepare(struct rp

if (!call_close) {
/* Note: exit _without_ calling nfs4_close_done */
- task->tk_action = NULL;
- nfs4_sequence_done(task, &calldata->res.seq_res);
- goto out;
+ goto out_no_action;
}

if (calldata->arg.fmode == 0) {
task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];
if (calldata->roc &&
pnfs_roc_drain(inode, &calldata->roc_barrier, task))
- goto out;
+ goto out_wait;
}

nfs_fattr_init(calldata->res.fattr);
@@ -2191,8 +2190,12 @@ static void nfs4_close_prepare(struct rp
&calldata->res.seq_res,
task) != 0)
nfs_release_seqid(calldata->arg.seqid);
-out:
dprintk("%s: done!\n", __func__);
+ return;
+out_no_action:
+ task->tk_action = NULL;
+out_wait:
+ nfs4_sequence_done(task, &calldata->res.seq_res);
}

static const struct rpc_call_ops nfs4_close_ops = {
@@ -4423,12 +4426,10 @@ static void nfs4_locku_prepare(struct rp
struct nfs4_unlockdata *calldata = data;

if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
- return;
+ goto out_wait;
if (test_bit(NFS_LOCK_INITIALIZED, &calldata->lsp->ls_flags) == 0) {
/* Note: exit _without_ running nfs4_locku_done */
- task->tk_action = NULL;
- nfs4_sequence_done(task, &calldata->res.seq_res);
- return;
+ goto out_no_action;
}
calldata->timestamp = jiffies;
if (nfs4_setup_sequence(calldata->server,
@@ -4436,6 +4437,11 @@ static void nfs4_locku_prepare(struct rp
&calldata->res.seq_res,
task) != 0)
nfs_release_seqid(calldata->arg.seqid);
+ return;
+out_no_action:
+ task->tk_action = NULL;
+out_wait:
+ nfs4_sequence_done(task, &calldata->res.seq_res);
}

static const struct rpc_call_ops nfs4_locku_ops = {
@@ -4576,7 +4582,7 @@ static void nfs4_lock_prepare(struct rpc

dprintk("%s: begin!\n", __func__);
if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)
- return;
+ goto out_wait;
/* Do we need to do an open_to_lock_owner? */
if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED)) {
if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0) {
@@ -4596,6 +4602,8 @@ static void nfs4_lock_prepare(struct rpc
nfs_release_seqid(data->arg.open_seqid);
out_release_lock_seqid:
nfs_release_seqid(data->arg.lock_seqid);
+out_wait:
+ nfs4_sequence_done(task, &data->res.seq_res);
dprintk("%s: done!, ret = %d\n", __func__, data->rpc_status);
}