xref: /openbmc/linux/fs/ocfs2/slot_map.c (revision 643d1f7f) 
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 
45 static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
46 				    s16 global);
47 static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
48 			      s16 slot_num,
49 			      s16 node_num);
50 
51 /* post the slot information on disk into our slot_info struct. */
52 void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
53 {
54 	int i;
55 	__le16 *disk_info;
56 
57 	/* we don't read the slot block here as ocfs2_super_lock
58 	 * should've made sure we have the most recent copy. */
59 	spin_lock(&si->si_lock);
60 	disk_info = (__le16 *) si->si_bh->b_data;
61 
62 	for (i = 0; i < si->si_size; i++)
63 		si->si_global_node_nums[i] = le16_to_cpu(disk_info[i]);
64 
65 	spin_unlock(&si->si_lock);
66 }
67 
68 /* post the our slot info stuff into it's destination bh and write it
69  * out. */
70 int ocfs2_update_disk_slots(struct ocfs2_super *osb,
71 			    struct ocfs2_slot_info *si)
72 {
73 	int status, i;
74 	__le16 *disk_info = (__le16 *) si->si_bh->b_data;
75 
76 	spin_lock(&si->si_lock);
77 	for (i = 0; i < si->si_size; i++)
78 		disk_info[i] = cpu_to_le16(si->si_global_node_nums[i]);
79 	spin_unlock(&si->si_lock);
80 
81 	status = ocfs2_write_block(osb, si->si_bh, si->si_inode);
82 	if (status < 0)
83 		mlog_errno(status);
84 
85 	return status;
86 }
87 
88 /* try to find global node in the slot info. Returns
89  * OCFS2_INVALID_SLOT if nothing is found. */
90 static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
91 				    s16 global)
92 {
93 	int i;
94 	s16 ret = OCFS2_INVALID_SLOT;
95 
96 	for(i = 0; i < si->si_num_slots; i++) {
97 		if (global == si->si_global_node_nums[i]) {
98 			ret = (s16) i;
99 			break;
100 		}
101 	}
102 	return ret;
103 }
104 
105 static s16 __ocfs2_find_empty_slot(struct ocfs2_slot_info *si, s16 preferred)
106 {
107 	int i;
108 	s16 ret = OCFS2_INVALID_SLOT;
109 
110 	if (preferred >= 0 && preferred < si->si_num_slots) {
111 		if (OCFS2_INVALID_SLOT == si->si_global_node_nums[preferred]) {
112 			ret = preferred;
113 			goto out;
114 		}
115 	}
116 
117 	for(i = 0; i < si->si_num_slots; i++) {
118 		if (OCFS2_INVALID_SLOT == si->si_global_node_nums[i]) {
119 			ret = (s16) i;
120 			break;
121 		}
122 	}
123 out:
124 	return ret;
125 }
126 
127 s16 ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
128 			   s16 global)
129 {
130 	s16 ret;
131 
132 	spin_lock(&si->si_lock);
133 	ret = __ocfs2_node_num_to_slot(si, global);
134 	spin_unlock(&si->si_lock);
135 	return ret;
136 }
137 
138 static void __ocfs2_fill_slot(struct ocfs2_slot_info *si,
139 			      s16 slot_num,
140 			      s16 node_num)
141 {
142 	BUG_ON(slot_num == OCFS2_INVALID_SLOT);
143 	BUG_ON(slot_num >= si->si_num_slots);
144 	BUG_ON((node_num != O2NM_INVALID_NODE_NUM) &&
145 	       (node_num >= O2NM_MAX_NODES));
146 
147 	si->si_global_node_nums[slot_num] = node_num;
148 }
149 
150 void ocfs2_clear_slot(struct ocfs2_slot_info *si,
151 		      s16 slot_num)
152 {
153 	spin_lock(&si->si_lock);
154 	__ocfs2_fill_slot(si, slot_num, OCFS2_INVALID_SLOT);
155 	spin_unlock(&si->si_lock);
156 }
157 
158 int ocfs2_init_slot_info(struct ocfs2_super *osb)
159 {
160 	int status, i;
161 	u64 blkno;
162 	struct inode *inode = NULL;
163 	struct buffer_head *bh = NULL;
164 	struct ocfs2_slot_info *si;
165 
166 	si = kzalloc(sizeof(struct ocfs2_slot_info), GFP_KERNEL);
167 	if (!si) {
168 		status = -ENOMEM;
169 		mlog_errno(status);
170 		goto bail;
171 	}
172 
173 	spin_lock_init(&si->si_lock);
174 	si->si_num_slots = osb->max_slots;
175 	si->si_size = OCFS2_MAX_SLOTS;
176 
177 	for(i = 0; i < si->si_num_slots; i++)
178 		si->si_global_node_nums[i] = OCFS2_INVALID_SLOT;
179 
180 	inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
181 					    OCFS2_INVALID_SLOT);
182 	if (!inode) {
183 		status = -EINVAL;
184 		mlog_errno(status);
185 		goto bail;
186 	}
187 
188 	status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL, NULL);
189 	if (status < 0) {
190 		mlog_errno(status);
191 		goto bail;
192 	}
193 
194 	status = ocfs2_read_block(osb, blkno, &bh, 0, inode);
195 	if (status < 0) {
196 		mlog_errno(status);
197 		goto bail;
198 	}
199 
200 	si->si_inode = inode;
201 	si->si_bh = bh;
202 	osb->slot_info = si;
203 bail:
204 	if (status < 0 && si)
205 		ocfs2_free_slot_info(si);
206 
207 	return status;
208 }
209 
210 void ocfs2_free_slot_info(struct ocfs2_slot_info *si)
211 {
212 	if (si->si_inode)
213 		iput(si->si_inode);
214 	if (si->si_bh)
215 		brelse(si->si_bh);
216 	kfree(si);
217 }
218 
219 int ocfs2_find_slot(struct ocfs2_super *osb)
220 {
221 	int status;
222 	s16 slot;
223 	struct ocfs2_slot_info *si;
224 
225 	mlog_entry_void();
226 
227 	si = osb->slot_info;
228 
229 	ocfs2_update_slot_info(si);
230 
231 	spin_lock(&si->si_lock);
232 	/* search for ourselves first and take the slot if it already
233 	 * exists. Perhaps we need to mark this in a variable for our
234 	 * own journal recovery? Possibly not, though we certainly
235 	 * need to warn to the user */
236 	slot = __ocfs2_node_num_to_slot(si, osb->node_num);
237 	if (slot == OCFS2_INVALID_SLOT) {
238 		/* if no slot yet, then just take 1st available
239 		 * one. */
240 		slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);
241 		if (slot == OCFS2_INVALID_SLOT) {
242 			spin_unlock(&si->si_lock);
243 			mlog(ML_ERROR, "no free slots available!\n");
244 			status = -EINVAL;
245 			goto bail;
246 		}
247 	} else
248 		mlog(ML_NOTICE, "slot %d is already allocated to this node!\n",
249 		     slot);
250 
251 	__ocfs2_fill_slot(si, slot, osb->node_num);
252 	osb->slot_num = slot;
253 	spin_unlock(&si->si_lock);
254 
255 	mlog(0, "taking node slot %d\n", osb->slot_num);
256 
257 	status = ocfs2_update_disk_slots(osb, si);
258 	if (status < 0)
259 		mlog_errno(status);
260 
261 bail:
262 	mlog_exit(status);
263 	return status;
264 }
265 
266 void ocfs2_put_slot(struct ocfs2_super *osb)
267 {
268 	int status;
269 	struct ocfs2_slot_info *si = osb->slot_info;
270 
271 	if (!si)
272 		return;
273 
274 	ocfs2_update_slot_info(si);
275 
276 	spin_lock(&si->si_lock);
277 	__ocfs2_fill_slot(si, osb->slot_num, OCFS2_INVALID_SLOT);
278 	osb->slot_num = OCFS2_INVALID_SLOT;
279 	spin_unlock(&si->si_lock);
280 
281 	status = ocfs2_update_disk_slots(osb, si);
282 	if (status < 0) {
283 		mlog_errno(status);
284 		goto bail;
285 	}
286 
287 bail:
288 	osb->slot_info = NULL;
289 	ocfs2_free_slot_info(si);
290 }
291 
292