1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * slot_map.c
5 *
6 *
7 *
8 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 */
25
26#include <linux/types.h>
27#include <linux/slab.h>
28#include <linux/highmem.h>
29
30#define MLOG_MASK_PREFIX ML_SUPER
31#include <cluster/masklog.h>
32
33#include "ocfs2.h"
34
35#include "dlmglue.h"
36#include "extent_map.h"
37#include "heartbeat.h"
38#include "inode.h"
39#include "slot_map.h"
40#include "super.h"
41#include "sysfile.h"
42
43#include "buffer_head_io.h"
44
45static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
46				    s16 global);
47static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
48			      s16 slot_num,
49			      s16 node_num);
50
51/* Use the slot information we've collected to create a map of mounted
52 * nodes. Should be holding an EX on super block. assumes slot info is
53 * up to date. Note that we call this *after* we find a slot, so our
54 * own node should be set in the map too... */
55void ocfs2_populate_mounted_map(struct ocfs2_super *osb)
56{
57	int i;
58	struct ocfs2_slot_info *si = osb->slot_info;
59
60	spin_lock(&si->si_lock);
61
62	for (i = 0; i < si->si_size; i++)
63		if (si->si_global_node_nums[i] != OCFS2_INVALID_SLOT)
64			ocfs2_node_map_set_bit(osb, &osb->mounted_map,
65					      si->si_global_node_nums[i]);
66
67	spin_unlock(&si->si_lock);
68}
69
70/* post the slot information on disk into our slot_info struct. */
71void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
72{
73	int i;
74	__le16 *disk_info;
75
76	/* we don't read the slot block here as ocfs2_super_lock
77	 * should've made sure we have the most recent copy. */
78	spin_lock(&si->si_lock);
79	disk_info = (__le16 *) si->si_bh->b_data;
80
81	for (i = 0; i < si->si_size; i++)
82		si->si_global_node_nums[i] = le16_to_cpu(disk_info[i]);
83
84	spin_unlock(&si->si_lock);
85}
86
87/* post the our slot info stuff into it's destination bh and write it
88 * out. */
89int ocfs2_update_disk_slots(struct ocfs2_super *osb,
90			    struct ocfs2_slot_info *si)
91{
92	int status, i;
93	__le16 *disk_info = (__le16 *) si->si_bh->b_data;
94
95	spin_lock(&si->si_lock);
96	for (i = 0; i < si->si_size; i++)
97		disk_info[i] = cpu_to_le16(si->si_global_node_nums[i]);
98	spin_unlock(&si->si_lock);
99
100	status = ocfs2_write_block(osb, si->si_bh, si->si_inode);
101	if (status < 0)
102		mlog_errno(status);
103
104	return status;
105}
106
107/* try to find global node in the slot info. Returns
108 * OCFS2_INVALID_SLOT if nothing is found. */
109static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
110				    s16 global)
111{
112	int i;
113	s16 ret = OCFS2_INVALID_SLOT;
114
115	for(i = 0; i < si->si_num_slots; i++) {
116		if (global == si->si_global_node_nums[i]) {
117			ret = (s16) i;
118			break;
119		}
120	}
121	return ret;
122}
123
124static s16 __ocfs2_find_empty_slot(struct ocfs2_slot_info *si)
125{
126	int i;
127	s16 ret = OCFS2_INVALID_SLOT;
128
129	for(i = 0; i < si->si_num_slots; i++) {
130		if (OCFS2_INVALID_SLOT == si->si_global_node_nums[i]) {
131			ret = (s16) i;
132			break;
133		}
134	}
135	return ret;
136}
137
138s16 ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
139			   s16 global)
140{
141	s16 ret;
142
143	spin_lock(&si->si_lock);
144	ret = __ocfs2_node_num_to_slot(si, global);
145	spin_unlock(&si->si_lock);
146	return ret;
147}
148
149static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
150			      s16 slot_num,
151			      s16 node_num)
152{
153	BUG_ON(slot_num == OCFS2_INVALID_SLOT);
154	BUG_ON(slot_num >= si->si_num_slots);
155	BUG_ON((node_num != O2NM_INVALID_NODE_NUM) &&
156	       (node_num >= O2NM_MAX_NODES));
157
158	si->si_global_node_nums[slot_num] = node_num;
159}
160
161void ocfs2_clear_slot(struct ocfs2_slot_info *si,
162		      s16 slot_num)
163{
164	spin_lock(&si->si_lock);
165	__ocfs2_fill_slot(si, slot_num, OCFS2_INVALID_SLOT);
166	spin_unlock(&si->si_lock);
167}
168
169int ocfs2_init_slot_info(struct ocfs2_super *osb)
170{
171	int status, i;
172	u64 blkno;
173	struct inode *inode = NULL;
174	struct buffer_head *bh = NULL;
175	struct ocfs2_slot_info *si;
176
177	si = kzalloc(sizeof(struct ocfs2_slot_info), GFP_KERNEL);
178	if (!si) {
179		status = -ENOMEM;
180		mlog_errno(status);
181		goto bail;
182	}
183
184	spin_lock_init(&si->si_lock);
185	si->si_num_slots = osb->max_slots;
186	si->si_size = OCFS2_MAX_SLOTS;
187
188	for(i = 0; i < si->si_num_slots; i++)
189		si->si_global_node_nums[i] = OCFS2_INVALID_SLOT;
190
191	inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
192					    OCFS2_INVALID_SLOT);
193	if (!inode) {
194		status = -EINVAL;
195		mlog_errno(status);
196		goto bail;
197	}
198
199	status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL, NULL);
200	if (status < 0) {
201		mlog_errno(status);
202		goto bail;
203	}
204
205	status = ocfs2_read_block(osb, blkno, &bh, 0, inode);
206	if (status < 0) {
207		mlog_errno(status);
208		goto bail;
209	}
210
211	si->si_inode = inode;
212	si->si_bh = bh;
213	osb->slot_info = si;
214bail:
215	if (status < 0 && si)
216		ocfs2_free_slot_info(si);
217
218	return status;
219}
220
221void ocfs2_free_slot_info(struct ocfs2_slot_info *si)
222{
223	if (si->si_inode)
224		iput(si->si_inode);
225	if (si->si_bh)
226		brelse(si->si_bh);
227	kfree(si);
228}
229
230int ocfs2_find_slot(struct ocfs2_super *osb)
231{
232	int status;
233	s16 slot;
234	struct ocfs2_slot_info *si;
235
236	mlog_entry_void();
237
238	si = osb->slot_info;
239
240	ocfs2_update_slot_info(si);
241
242	spin_lock(&si->si_lock);
243	/* search for ourselves first and take the slot if it already
244	 * exists. Perhaps we need to mark this in a variable for our
245	 * own journal recovery? Possibly not, though we certainly
246	 * need to warn to the user */
247	slot = __ocfs2_node_num_to_slot(si, osb->node_num);
248	if (slot == OCFS2_INVALID_SLOT) {
249		/* if no slot yet, then just take 1st available
250		 * one. */
251		slot = __ocfs2_find_empty_slot(si);
252		if (slot == OCFS2_INVALID_SLOT) {
253			spin_unlock(&si->si_lock);
254			mlog(ML_ERROR, "no free slots available!\n");
255			status = -EINVAL;
256			goto bail;
257		}
258	} else
259		mlog(ML_NOTICE, "slot %d is already allocated to this node!\n",
260		     slot);
261
262	__ocfs2_fill_slot(si, slot, osb->node_num);
263	osb->slot_num = slot;
264	spin_unlock(&si->si_lock);
265
266	mlog(0, "taking node slot %d\n", osb->slot_num);
267
268	status = ocfs2_update_disk_slots(osb, si);
269	if (status < 0)
270		mlog_errno(status);
271
272bail:
273	mlog_exit(status);
274	return status;
275}
276
277void ocfs2_put_slot(struct ocfs2_super *osb)
278{
279	int status;
280	struct ocfs2_slot_info *si = osb->slot_info;
281
282	if (!si)
283		return;
284
285	ocfs2_update_slot_info(si);
286
287	spin_lock(&si->si_lock);
288	__ocfs2_fill_slot(si, osb->slot_num, OCFS2_INVALID_SLOT);
289	osb->slot_num = OCFS2_INVALID_SLOT;
290	spin_unlock(&si->si_lock);
291
292	status = ocfs2_update_disk_slots(osb, si);
293	if (status < 0) {
294		mlog_errno(status);
295		goto bail;
296	}
297
298bail:
299	osb->slot_info = NULL;
300	ocfs2_free_slot_info(si);
301}
302