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// SPDX-License-Identifier: GPL-2.0
/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is included
* in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
* http://www.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
/*
* Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2011, 2012, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* Lustre is a trademark of Sun Microsystems, Inc.
*
* lustre/include/lustre_mdc.h
*
* MDS data structures.
* See also lustre_idl.h for wire formats of requests.
*/
#ifndef _LUSTRE_MDC_H
#define _LUSTRE_MDC_H
/** \defgroup mdc mdc
*
* @{
*/
#include <linux/fs.h>
#include <linux/dcache.h>
#include <lustre_intent.h>
#include <lustre_handles.h>
#include <linux/libcfs/libcfs.h>
#include <obd_class.h>
#include <lustre_lib.h>
#include <lustre_dlm.h>
#include <lustre_export.h>
struct ptlrpc_client;
struct obd_export;
struct ptlrpc_request;
struct obd_device;
/**
* Serializes in-flight MDT-modifying RPC requests to preserve idempotency.
*
* This mutex is used to implement execute-once semantics on the MDT.
* The MDT stores the last transaction ID and result for every client in
* its last_rcvd file. If the client doesn't get a reply, it can safely
* resend the request and the MDT will reconstruct the reply being aware
* that the request has already been executed. Without this lock,
* execution status of concurrent in-flight requests would be
* overwritten.
*
* This design limits the extent to which we can keep a full pipeline of
* in-flight requests from a single client. This limitation could be
* overcome by allowing multiple slots per client in the last_rcvd file.
*/
struct mdc_rpc_lock {
/** Lock protecting in-flight RPC concurrency. */
struct mutex rpcl_mutex;
/** Intent associated with currently executing request. */
struct lookup_intent *rpcl_it;
/** Used for MDS/RPC load testing purposes. */
int rpcl_fakes;
};
#define MDC_FAKE_RPCL_IT ((void *)0x2c0012bfUL)
static inline void mdc_init_rpc_lock(struct mdc_rpc_lock *lck)
{
mutex_init(&lck->rpcl_mutex);
lck->rpcl_it = NULL;
}
static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
struct lookup_intent *it)
{
if (it && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
it->it_op == IT_LAYOUT || it->it_op == IT_READDIR))
return;
/* This would normally block until the existing request finishes.
* If fail_loc is set it will block until the regular request is
* done, then set rpcl_it to MDC_FAKE_RPCL_IT. Once that is set
* it will only be cleared when all fake requests are finished.
* Only when all fake requests are finished can normal requests
* be sent, to ensure they are recoverable again.
*/
again:
mutex_lock(&lck->rpcl_mutex);
if (CFS_FAIL_CHECK_QUIET(OBD_FAIL_MDC_RPCS_SEM)) {
lck->rpcl_it = MDC_FAKE_RPCL_IT;
lck->rpcl_fakes++;
mutex_unlock(&lck->rpcl_mutex);
return;
}
/* This will only happen when the CFS_FAIL_CHECK() was
* just turned off but there are still requests in progress.
* Wait until they finish. It doesn't need to be efficient
* in this extremely rare case, just have low overhead in
* the common case when it isn't true.
*/
while (unlikely(lck->rpcl_it == MDC_FAKE_RPCL_IT)) {
mutex_unlock(&lck->rpcl_mutex);
schedule_timeout(HZ / 4);
goto again;
}
LASSERT(!lck->rpcl_it);
lck->rpcl_it = it;
}
static inline void mdc_put_rpc_lock(struct mdc_rpc_lock *lck,
struct lookup_intent *it)
{
if (it && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
it->it_op == IT_LAYOUT || it->it_op == IT_READDIR))
return;
if (lck->rpcl_it == MDC_FAKE_RPCL_IT) { /* OBD_FAIL_MDC_RPCS_SEM */
mutex_lock(&lck->rpcl_mutex);
LASSERTF(lck->rpcl_fakes > 0, "%d\n", lck->rpcl_fakes);
lck->rpcl_fakes--;
if (lck->rpcl_fakes == 0)
lck->rpcl_it = NULL;
} else {
LASSERTF(it == lck->rpcl_it, "%p != %p\n", it, lck->rpcl_it);
lck->rpcl_it = NULL;
}
mutex_unlock(&lck->rpcl_mutex);
}
static inline void mdc_get_mod_rpc_slot(struct ptlrpc_request *req,
struct lookup_intent *it)
{
struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
u32 opc;
u16 tag;
opc = lustre_msg_get_opc(req->rq_reqmsg);
tag = obd_get_mod_rpc_slot(cli, opc, it);
lustre_msg_set_tag(req->rq_reqmsg, tag);
}
static inline void mdc_put_mod_rpc_slot(struct ptlrpc_request *req,
struct lookup_intent *it)
{
struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
u32 opc;
u16 tag;
opc = lustre_msg_get_opc(req->rq_reqmsg);
tag = lustre_msg_get_tag(req->rq_reqmsg);
obd_put_mod_rpc_slot(cli, opc, it, tag);
}
/**
* Update the maximum possible easize.
*
* This value is learned from ptlrpc replies sent by the MDT. The
* default easize is initialized to the minimum value but allowed
* to grow up to a single page in size if required to handle the
* common case.
*
* \see client_obd::cl_default_mds_easize
*
* \param[in] exp export for MDC device
* \param[in] body body of ptlrpc reply from MDT
*
*/
static inline void mdc_update_max_ea_from_body(struct obd_export *exp,
struct mdt_body *body)
{
if (body->mbo_valid & OBD_MD_FLMODEASIZE) {
struct client_obd *cli = &exp->exp_obd->u.cli;
u32 def_easize;
if (cli->cl_max_mds_easize < body->mbo_max_mdsize)
cli->cl_max_mds_easize = body->mbo_max_mdsize;
def_easize = min_t(__u32, body->mbo_max_mdsize,
OBD_MAX_DEFAULT_EA_SIZE);
cli->cl_default_mds_easize = def_easize;
}
}
/* mdc/mdc_locks.c */
int it_open_error(int phase, struct lookup_intent *it);
static inline bool cl_is_lov_delay_create(unsigned int flags)
{
return (flags & O_LOV_DELAY_CREATE) == O_LOV_DELAY_CREATE;
}
static inline void cl_lov_delay_create_clear(unsigned int *flags)
{
if ((*flags & O_LOV_DELAY_CREATE) == O_LOV_DELAY_CREATE)
*flags &= ~O_LOV_DELAY_CREATE;
}
/** @} mdc */
#endif
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