3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
commit ed7e5423014ad89720fcf315c0b73f2c5d0c7bd2 upstream.
An NFS4ERR_RECALLCONFLICT is returned by server from a GET_LAYOUT
only when a Server Sent a RECALL do to that GET_LAYOUT, or
the RECALL and GET_LAYOUT crossed on the wire.
In any way this means we want to wait at most until in-flight IO
is finished and the RECALL can be satisfied.
So a proper wait here is more like 1/10 of a second, not 15 seconds
like we have now. In case of a server bug we delay exponentially
longer on each retry.
Current code totally craps out performance of very large files on
most pnfs-objects layouts, because of how the map changes when the
file has grown into the next raid group.
[Stable: This will patch back to 3.9. If there are earlier still
maintained trees, please tell me I'll send a patch]
Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 34 ++++++++++++++++++++++++++++++----
1 file changed, 30 insertions(+), 4 deletions(-)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7057,9 +7057,9 @@ static void nfs4_layoutget_done(struct r
struct nfs_server *server = NFS_SERVER(inode);
struct pnfs_layout_hdr *lo;
struct nfs4_state *state = NULL;
- unsigned long timeo, giveup;
+ unsigned long timeo, now, giveup;
- dprintk("--> %s\n", __func__);
+ dprintk("--> %s tk_status => %d\n", __func__, -task->tk_status);
if (!nfs41_sequence_done(task, &lgp->res.seq_res))
goto out;
@@ -7067,12 +7067,38 @@ static void nfs4_layoutget_done(struct r
switch (task->tk_status) {
case 0:
goto out;
+ /*
+ * NFS4ERR_LAYOUTTRYLATER is a conflict with another client
+ * (or clients) writing to the same RAID stripe
+ */
case -NFS4ERR_LAYOUTTRYLATER:
+ /*
+ * NFS4ERR_RECALLCONFLICT is when conflict with self (must recall
+ * existing layout before getting a new one).
+ */
case -NFS4ERR_RECALLCONFLICT:
timeo = rpc_get_timeout(task->tk_client);
giveup = lgp->args.timestamp + timeo;
- if (time_after(giveup, jiffies))
- task->tk_status = -NFS4ERR_DELAY;
+ now = jiffies;
+ if (time_after(giveup, now)) {
+ unsigned long delay;
+
+ /* Delay for:
+ * - Not less then NFS4_POLL_RETRY_MIN.
+ * - One last time a jiffie before we give up
+ * - exponential backoff (time_now minus start_attempt)
+ */
+ delay = max_t(unsigned long, NFS4_POLL_RETRY_MIN,
+ min((giveup - now - 1),
+ now - lgp->args.timestamp));
+
+ dprintk("%s: NFS4ERR_RECALLCONFLICT waiting %lu\n",
+ __func__, delay);
+ rpc_delay(task, delay);
+ task->tk_status = 0;
+ rpc_restart_call_prepare(task);
+ goto out; /* Do not call nfs4_async_handle_error() */
+ }
break;
case -NFS4ERR_EXPIRED:
case -NFS4ERR_BAD_STATEID:
--
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