2014-01-28 23:01:21

by Andy Adamson

[permalink] [raw]
Subject: [PATCH 0/1] NFSv4.1 free slot before resending I/O to MDS

From: Andy Adamson <[email protected]>

Replaces NFSv4.1 Do not pre-allocate slots in nfs4_end_drain_slot_tbl.

Andy Adamson (1):
NFSv4.1 free slot before resending I/O to MDS

fs/nfs/nfs4filelayout.c | 6 ++++++
fs/nfs/nfs4session.c | 1 +
2 files changed, 7 insertions(+)

--
1.8.3.1



2014-01-28 23:01:21

by Andy Adamson

[permalink] [raw]
Subject: [PATCH 1/1] NFSv4.1 free slot before resending I/O to MDS

From: Andy Adamson <[email protected]>

Free an allocated slot from nfs41_wake_and_assign_slot prior to rpc_exit.
Prevents a state_manager hang when draining a data server session.

Signed-off-by: Andy Adamson <[email protected]>
---
fs/nfs/nfs4filelayout.c | 6 ++++++
fs/nfs/nfs4session.c | 1 +
2 files changed, 7 insertions(+)

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 03fd8be..9611999 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -314,6 +314,9 @@ static void filelayout_read_prepare(struct rpc_task *task, void *data)
if (filelayout_reset_to_mds(rdata->header->lseg)) {
dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
filelayout_reset_read(rdata);
+ if (rdata->res.seq_res.sr_slot != NULL)
+ nfs4_free_slot(&rdata->ds_clp->cl_session->fc_slot_table,
+ rdata->res.seq_res.sr_slot);
rpc_exit(task, 0);
return;
}
@@ -425,6 +428,9 @@ static void filelayout_write_prepare(struct rpc_task *task, void *data)
if (filelayout_reset_to_mds(wdata->header->lseg)) {
dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
filelayout_reset_write(wdata);
+ if (wdata->res.seq_res.sr_slot != NULL)
+ nfs4_free_slot(&wdata->ds_clp->cl_session->fc_slot_table,
+ wdata->res.seq_res.sr_slot);
rpc_exit(task, 0);
return;
}
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index cf883c7..5226846 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -98,6 +98,7 @@ void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
slotid, tbl->highest_used_slotid);
}
+EXPORT_SYMBOL_GPL(nfs4_free_slot);

static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
u32 slotid, u32 seq_init, gfp_t gfp_mask)
--
1.8.3.1


2014-01-28 23:28:08

by Trond Myklebust

[permalink] [raw]
Subject: Re: [PATCH 1/1] NFSv4.1 free slot before resending I/O to MDS

Hi Andy,

On Jan 28, 2014, at 18:01, <[email protected]> <[email protected]> wrote:

> From: Andy Adamson <[email protected]>
>
> Free an allocated slot from nfs41_wake_and_assign_slot prior to rpc_exit.
> Prevents a state_manager hang when draining a data server session.
>
> Signed-off-by: Andy Adamson <[email protected]>
> ---
> fs/nfs/nfs4filelayout.c | 6 ++++++
> fs/nfs/nfs4session.c | 1 +
> 2 files changed, 7 insertions(+)
>
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index 03fd8be..9611999 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -314,6 +314,9 @@ static void filelayout_read_prepare(struct rpc_task *task, void *data)
> if (filelayout_reset_to_mds(rdata->header->lseg)) {
> dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
> filelayout_reset_read(rdata);
> + if (rdata->res.seq_res.sr_slot != NULL)
> + nfs4_free_slot(&rdata->ds_clp->cl_session->fc_slot_table,
> + rdata->res.seq_res.sr_slot);
> rpc_exit(task, 0);
> return;
> }
> @@ -425,6 +428,9 @@ static void filelayout_write_prepare(struct rpc_task *task, void *data)
> if (filelayout_reset_to_mds(wdata->header->lseg)) {
> dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
> filelayout_reset_write(wdata);
> + if (wdata->res.seq_res.sr_slot != NULL)
> + nfs4_free_slot(&wdata->ds_clp->cl_session->fc_slot_table,
> + wdata->res.seq_res.sr_slot);
> rpc_exit(task, 0);
> return;
> }
> diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
> index cf883c7..5226846 100644
> --- a/fs/nfs/nfs4session.c
> +++ b/fs/nfs/nfs4session.c
> @@ -98,6 +98,7 @@ void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
> dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
> slotid, tbl->highest_used_slotid);
> }
> +EXPORT_SYMBOL_GPL(nfs4_free_slot);
>
> static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl,
> u32 slotid, u32 seq_init, gfp_t gfp_mask)

OK, this fix makes a lot more sense to me.

However, since rpc_exit() will trigger a call to the rpc_call_ops->rpc_call_done(), then perhaps a better alternative would be to have filelayout_read_call_done() and filelayout_write_call_done() call nfs41_sequence_done() if the test for NFS_IOHDR_REDO succeeds? Otherwise, it looks as if we still have the potential for a leak.

--
Trond Myklebust
Linux NFS client maintainer