lustre_mdc.h revision 23f14e79ace301c1e46b52344ce02e72254c57b6 
1/*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 *
24 * GPL HEADER END
25 */
26/*
27 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 */
30/*
31 * Copyright (c) 2011, 2012, Intel Corporation.
32 */
33/*
34 * This file is part of Lustre, http://www.lustre.org/
35 * Lustre is a trademark of Sun Microsystems, Inc.
36 *
37 * lustre/include/lustre_mdc.h
38 *
39 * MDS data structures.
40 * See also lustre_idl.h for wire formats of requests.
41 */
42
43#ifndef _LUSTRE_MDC_H
44#define _LUSTRE_MDC_H
45
46/** \defgroup mdc mdc
47 *
48 * @{
49 */
50
51# include <linux/fs.h>
52# include <linux/dcache.h>
53# ifdef CONFIG_FS_POSIX_ACL
54#  include <linux/posix_acl_xattr.h>
55# endif /* CONFIG_FS_POSIX_ACL */
56# include <linux/lustre_intent.h>
57#include <lustre_handles.h>
58#include <linux/libcfs/libcfs.h>
59#include <obd_class.h>
60#include <lustre/lustre_idl.h>
61#include <lustre_lib.h>
62#include <lustre_dlm.h>
63#include <lustre_export.h>
64
65struct ptlrpc_client;
66struct obd_export;
67struct ptlrpc_request;
68struct obd_device;
69
70struct mdc_rpc_lock {
71	struct mutex		rpcl_mutex;
72	struct lookup_intent	*rpcl_it;
73	int			rpcl_fakes;
74};
75
76#define MDC_FAKE_RPCL_IT ((void *)0x2c0012bfUL)
77
78static inline void mdc_init_rpc_lock(struct mdc_rpc_lock *lck)
79{
80	mutex_init(&lck->rpcl_mutex);
81	lck->rpcl_it = NULL;
82}
83
84static inline void mdc_get_rpc_lock(struct mdc_rpc_lock *lck,
85				    struct lookup_intent *it)
86{
87	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
88			   it->it_op == IT_LAYOUT))
89		return;
90
91	/* This would normally block until the existing request finishes.
92	 * If fail_loc is set it will block until the regular request is
93	 * done, then set rpcl_it to MDC_FAKE_RPCL_IT.  Once that is set
94	 * it will only be cleared when all fake requests are finished.
95	 * Only when all fake requests are finished can normal requests
96	 * be sent, to ensure they are recoverable again. */
97 again:
98	mutex_lock(&lck->rpcl_mutex);
99
100	if (CFS_FAIL_CHECK_QUIET(OBD_FAIL_MDC_RPCS_SEM)) {
101		lck->rpcl_it = MDC_FAKE_RPCL_IT;
102		lck->rpcl_fakes++;
103		mutex_unlock(&lck->rpcl_mutex);
104		return;
105	}
106
107	/* This will only happen when the CFS_FAIL_CHECK() was
108	 * just turned off but there are still requests in progress.
109	 * Wait until they finish.  It doesn't need to be efficient
110	 * in this extremely rare case, just have low overhead in
111	 * the common case when it isn't true. */
112	while (unlikely(lck->rpcl_it == MDC_FAKE_RPCL_IT)) {
113		mutex_unlock(&lck->rpcl_mutex);
114		schedule_timeout(cfs_time_seconds(1) / 4);
115		goto again;
116	}
117
118	LASSERT(lck->rpcl_it == NULL);
119	lck->rpcl_it = it;
120}
121
122static inline void mdc_put_rpc_lock(struct mdc_rpc_lock *lck,
123				    struct lookup_intent *it)
124{
125	if (it != NULL && (it->it_op == IT_GETATTR || it->it_op == IT_LOOKUP ||
126			   it->it_op == IT_LAYOUT))
127		return;
128
129	if (lck->rpcl_it == MDC_FAKE_RPCL_IT) { /* OBD_FAIL_MDC_RPCS_SEM */
130		mutex_lock(&lck->rpcl_mutex);
131
132		LASSERTF(lck->rpcl_fakes > 0, "%d\n", lck->rpcl_fakes);
133		lck->rpcl_fakes--;
134
135		if (lck->rpcl_fakes == 0)
136			lck->rpcl_it = NULL;
137
138	} else {
139		LASSERTF(it == lck->rpcl_it, "%p != %p\n", it, lck->rpcl_it);
140		lck->rpcl_it = NULL;
141	}
142
143	mutex_unlock(&lck->rpcl_mutex);
144}
145
146static inline void mdc_update_max_ea_from_body(struct obd_export *exp,
147					       struct mdt_body *body)
148{
149	if (body->valid & OBD_MD_FLMODEASIZE) {
150		if (exp->exp_obd->u.cli.cl_max_mds_easize < body->max_mdsize)
151			exp->exp_obd->u.cli.cl_max_mds_easize =
152						body->max_mdsize;
153		if (exp->exp_obd->u.cli.cl_max_mds_cookiesize <
154						body->max_cookiesize)
155			exp->exp_obd->u.cli.cl_max_mds_cookiesize =
156						body->max_cookiesize;
157	}
158}
159
160
161struct mdc_cache_waiter {
162	struct list_head	      mcw_entry;
163	wait_queue_head_t	     mcw_waitq;
164};
165
166/* mdc/mdc_locks.c */
167int it_disposition(struct lookup_intent *it, int flag);
168void it_clear_disposition(struct lookup_intent *it, int flag);
169void it_set_disposition(struct lookup_intent *it, int flag);
170int it_open_error(int phase, struct lookup_intent *it);
171
172/** @} mdc */
173
174#endif
175