diff options
Diffstat (limited to 'nfsv4.1-avoid-false-retries.patch')
| -rw-r--r-- | nfsv4.1-avoid-false-retries.patch | 260 |
1 files changed, 0 insertions, 260 deletions
diff --git a/nfsv4.1-avoid-false-retries.patch b/nfsv4.1-avoid-false-retries.patch deleted file mode 100644 index ebec54dab..000000000 --- a/nfsv4.1-avoid-false-retries.patch +++ /dev/null @@ -1,260 +0,0 @@ -From 675f11241a9f5b434effc7aee9eb84bf3d17d685 Mon Sep 17 00:00:00 2001 -From: Trond Myklebust <trond.myklebust@hammerspace.com> -Date: Wed, 20 Jun 2018 17:53:34 -0400 -Subject: [PATCH] NFSv4.1: Avoid false retries when RPC calls are interrupted - -A 'false retry' in NFSv4.1 occurs when the client attempts to transmit a -new RPC call using a slot+sequence number combination that references an -already cached one. Currently, the Linux NFS client will do this if a -user process interrupts an RPC call that is in progress. -The problem with doing so is that we defeat the main mechanism used by -the server to differentiate between a new call and a replayed one. Even -if the server is able to perfectly cache the arguments of the old call, -it cannot know if the client intended to replay or send a new call. - -The obvious fix is to bump the sequence number pre-emptively if an -RPC call is interrupted, but in order to deal with the corner cases -where the interrupted call is not actually received and processed by -the server, we need to interpret the error NFS4ERR_SEQ_MISORDERED -as a sign that we need to either wait or locate a correct sequence -number that lies between the value we sent, and the last value that -was acked by a SEQUENCE call on that slot. - -Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> ---- - fs/nfs/nfs4proc.c | 105 ++++++++++++++++++++----------------------- - fs/nfs/nfs4session.c | 5 ++- - fs/nfs/nfs4session.h | 5 ++- - 3 files changed, 55 insertions(+), 60 deletions(-) - -diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c -index 64ac80ec6b7b..3a6a9c9ee369 100644 ---- a/fs/nfs/nfs4proc.c -+++ b/fs/nfs/nfs4proc.c -@@ -730,13 +730,25 @@ static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res) - res->sr_slot = NULL; - } - -+static void nfs4_slot_sequence_record_sent(struct nfs4_slot *slot, -+ u32 seqnr) -+{ -+ if ((s32)(seqnr - slot->seq_nr_highest_sent) > 0) -+ slot->seq_nr_highest_sent = seqnr; -+} -+static void nfs4_slot_sequence_acked(struct nfs4_slot *slot, -+ u32 seqnr) -+{ -+ slot->seq_nr_highest_sent = seqnr; -+ slot->seq_nr_last_acked = seqnr; -+} -+ - static int nfs41_sequence_process(struct rpc_task *task, - struct nfs4_sequence_res *res) - { - struct nfs4_session *session; - struct nfs4_slot *slot = res->sr_slot; - struct nfs_client *clp; -- bool interrupted = false; - int ret = 1; - - if (slot == NULL) -@@ -747,16 +759,12 @@ static int nfs41_sequence_process(struct rpc_task *task, - - session = slot->table->session; - -- if (slot->interrupted) { -- if (res->sr_status != -NFS4ERR_DELAY) -- slot->interrupted = 0; -- interrupted = true; -- } -- - trace_nfs4_sequence_done(session, res); - /* Check the SEQUENCE operation status */ - switch (res->sr_status) { - case 0: -+ /* Mark this sequence number as having been acked */ -+ nfs4_slot_sequence_acked(slot, slot->seq_nr); - /* Update the slot's sequence and clientid lease timer */ - slot->seq_done = 1; - clp = session->clp; -@@ -771,9 +779,9 @@ static int nfs41_sequence_process(struct rpc_task *task, - * sr_status remains 1 if an RPC level error occurred. - * The server may or may not have processed the sequence - * operation.. -- * Mark the slot as having hosted an interrupted RPC call. - */ -- slot->interrupted = 1; -+ nfs4_slot_sequence_record_sent(slot, slot->seq_nr); -+ slot->seq_done = 1; - goto out; - case -NFS4ERR_DELAY: - /* The server detected a resend of the RPC call and -@@ -784,6 +792,7 @@ static int nfs41_sequence_process(struct rpc_task *task, - __func__, - slot->slot_nr, - slot->seq_nr); -+ nfs4_slot_sequence_acked(slot, slot->seq_nr); - goto out_retry; - case -NFS4ERR_RETRY_UNCACHED_REP: - case -NFS4ERR_SEQ_FALSE_RETRY: -@@ -791,6 +800,7 @@ static int nfs41_sequence_process(struct rpc_task *task, - * The server thinks we tried to replay a request. - * Retry the call after bumping the sequence ID. - */ -+ nfs4_slot_sequence_acked(slot, slot->seq_nr); - goto retry_new_seq; - case -NFS4ERR_BADSLOT: - /* -@@ -801,21 +811,28 @@ static int nfs41_sequence_process(struct rpc_task *task, - goto session_recover; - goto retry_nowait; - case -NFS4ERR_SEQ_MISORDERED: -+ nfs4_slot_sequence_record_sent(slot, slot->seq_nr); - /* -- * Was the last operation on this sequence interrupted? -- * If so, retry after bumping the sequence number. -+ * Were one or more calls using this slot interrupted? -+ * If the server never received the request, then our -+ * transmitted slot sequence number may be too high. - */ -- if (interrupted) -- goto retry_new_seq; -- /* -- * Could this slot have been previously retired? -- * If so, then the server may be expecting seq_nr = 1! -- */ -- if (slot->seq_nr != 1) { -- slot->seq_nr = 1; -+ if ((s32)(slot->seq_nr - slot->seq_nr_last_acked) > 1) { -+ slot->seq_nr--; - goto retry_nowait; - } -- goto session_recover; -+ /* -+ * RFC5661: -+ * A retry might be sent while the original request is -+ * still in progress on the replier. The replier SHOULD -+ * deal with the issue by returning NFS4ERR_DELAY as the -+ * reply to SEQUENCE or CB_SEQUENCE operation, but -+ * implementations MAY return NFS4ERR_SEQ_MISORDERED. -+ * -+ * Restart the search after a delay. -+ */ -+ slot->seq_nr = slot->seq_nr_highest_sent; -+ goto out_retry; - default: - /* Just update the slot sequence no. */ - slot->seq_done = 1; -@@ -906,17 +923,6 @@ static const struct rpc_call_ops nfs41_call_sync_ops = { - .rpc_call_done = nfs41_call_sync_done, - }; - --static void --nfs4_sequence_process_interrupted(struct nfs_client *client, -- struct nfs4_slot *slot, const struct cred *cred) --{ -- struct rpc_task *task; -- -- task = _nfs41_proc_sequence(client, cred, slot, true); -- if (!IS_ERR(task)) -- rpc_put_task_async(task); --} -- - #else /* !CONFIG_NFS_V4_1 */ - - static int nfs4_sequence_process(struct rpc_task *task, struct nfs4_sequence_res *res) -@@ -937,14 +943,6 @@ int nfs4_sequence_done(struct rpc_task *task, - } - EXPORT_SYMBOL_GPL(nfs4_sequence_done); - --static void --nfs4_sequence_process_interrupted(struct nfs_client *client, -- struct nfs4_slot *slot, const struct cred *cred) --{ -- WARN_ON_ONCE(1); -- slot->interrupted = 0; --} -- - #endif /* !CONFIG_NFS_V4_1 */ - - static void nfs41_sequence_res_init(struct nfs4_sequence_res *res) -@@ -985,26 +983,19 @@ int nfs4_setup_sequence(struct nfs_client *client, - task->tk_timeout = 0; - } - -- for (;;) { -- spin_lock(&tbl->slot_tbl_lock); -- /* The state manager will wait until the slot table is empty */ -- if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged) -- goto out_sleep; -- -- slot = nfs4_alloc_slot(tbl); -- if (IS_ERR(slot)) { -- /* Try again in 1/4 second */ -- if (slot == ERR_PTR(-ENOMEM)) -- task->tk_timeout = HZ >> 2; -- goto out_sleep; -- } -- spin_unlock(&tbl->slot_tbl_lock); -+ spin_lock(&tbl->slot_tbl_lock); -+ /* The state manager will wait until the slot table is empty */ -+ if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged) -+ goto out_sleep; - -- if (likely(!slot->interrupted)) -- break; -- nfs4_sequence_process_interrupted(client, -- slot, task->tk_msg.rpc_cred); -+ slot = nfs4_alloc_slot(tbl); -+ if (IS_ERR(slot)) { -+ /* Try again in 1/4 second */ -+ if (slot == ERR_PTR(-ENOMEM)) -+ task->tk_timeout = HZ >> 2; -+ goto out_sleep; - } -+ spin_unlock(&tbl->slot_tbl_lock); - - nfs4_sequence_attach_slot(args, res, slot); - -diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c -index a5489d70a724..39962c19744f 100644 ---- a/fs/nfs/nfs4session.c -+++ b/fs/nfs/nfs4session.c -@@ -110,6 +110,8 @@ static struct nfs4_slot *nfs4_new_slot(struct nfs4_slot_table *tbl, - slot->table = tbl; - slot->slot_nr = slotid; - slot->seq_nr = seq_init; -+ slot->seq_nr_highest_sent = seq_init; -+ slot->seq_nr_last_acked = seq_init - 1; - } - return slot; - } -@@ -276,7 +278,8 @@ static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl, - p = &tbl->slots; - while (*p) { - (*p)->seq_nr = ivalue; -- (*p)->interrupted = 0; -+ (*p)->seq_nr_highest_sent = ivalue; -+ (*p)->seq_nr_last_acked = ivalue - 1; - p = &(*p)->next; - } - tbl->highest_used_slotid = NFS4_NO_SLOT; -diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h -index 3c550f297561..230509b77121 100644 ---- a/fs/nfs/nfs4session.h -+++ b/fs/nfs/nfs4session.h -@@ -23,8 +23,9 @@ struct nfs4_slot { - unsigned long generation; - u32 slot_nr; - u32 seq_nr; -- unsigned int interrupted : 1, -- privileged : 1, -+ u32 seq_nr_last_acked; -+ u32 seq_nr_highest_sent; -+ unsigned int privileged : 1, - seq_done : 1; - }; - --- -2.20.1 - |