Root/fs/ocfs2/slot_map.c

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
46struct ocfs2_slot {
47    int sl_valid;
48    unsigned int sl_node_num;
49};
50
51struct ocfs2_slot_info {
52    int si_extended;
53    int si_slots_per_block;
54    struct inode *si_inode;
55    unsigned int si_blocks;
56    struct buffer_head **si_bh;
57    unsigned int si_num_slots;
58    struct ocfs2_slot *si_slots;
59};
60
61
62static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
63                    unsigned int node_num);
64
65static void ocfs2_invalidate_slot(struct ocfs2_slot_info *si,
66                  int slot_num)
67{
68    BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));
69    si->si_slots[slot_num].sl_valid = 0;
70}
71
72static void ocfs2_set_slot(struct ocfs2_slot_info *si,
73               int slot_num, unsigned int node_num)
74{
75    BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));
76
77    si->si_slots[slot_num].sl_valid = 1;
78    si->si_slots[slot_num].sl_node_num = node_num;
79}
80
81/* This version is for the extended slot map */
82static void ocfs2_update_slot_info_extended(struct ocfs2_slot_info *si)
83{
84    int b, i, slotno;
85    struct ocfs2_slot_map_extended *se;
86
87    slotno = 0;
88    for (b = 0; b < si->si_blocks; b++) {
89        se = (struct ocfs2_slot_map_extended *)si->si_bh[b]->b_data;
90        for (i = 0;
91             (i < si->si_slots_per_block) &&
92             (slotno < si->si_num_slots);
93             i++, slotno++) {
94            if (se->se_slots[i].es_valid)
95                ocfs2_set_slot(si, slotno,
96                           le32_to_cpu(se->se_slots[i].es_node_num));
97            else
98                ocfs2_invalidate_slot(si, slotno);
99        }
100    }
101}
102
103/*
104 * Post the slot information on disk into our slot_info struct.
105 * Must be protected by osb_lock.
106 */
107static void ocfs2_update_slot_info_old(struct ocfs2_slot_info *si)
108{
109    int i;
110    struct ocfs2_slot_map *sm;
111
112    sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;
113
114    for (i = 0; i < si->si_num_slots; i++) {
115        if (le16_to_cpu(sm->sm_slots[i]) == (u16)OCFS2_INVALID_SLOT)
116            ocfs2_invalidate_slot(si, i);
117        else
118            ocfs2_set_slot(si, i, le16_to_cpu(sm->sm_slots[i]));
119    }
120}
121
122static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
123{
124    /*
125     * The slot data will have been refreshed when ocfs2_super_lock
126     * was taken.
127     */
128    if (si->si_extended)
129        ocfs2_update_slot_info_extended(si);
130    else
131        ocfs2_update_slot_info_old(si);
132}
133
134int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
135{
136    int ret;
137    struct ocfs2_slot_info *si = osb->slot_info;
138
139    if (si == NULL)
140        return 0;
141
142    BUG_ON(si->si_blocks == 0);
143    BUG_ON(si->si_bh == NULL);
144
145    mlog(0, "Refreshing slot map, reading %u block(s)\n",
146         si->si_blocks);
147
148    /*
149     * We pass -1 as blocknr because we expect all of si->si_bh to
150     * be !NULL. Thus, ocfs2_read_blocks() will ignore blocknr. If
151     * this is not true, the read of -1 (UINT64_MAX) will fail.
152     */
153    ret = ocfs2_read_blocks(INODE_CACHE(si->si_inode), -1, si->si_blocks,
154                si->si_bh, OCFS2_BH_IGNORE_CACHE, NULL);
155    if (ret == 0) {
156        spin_lock(&osb->osb_lock);
157        ocfs2_update_slot_info(si);
158        spin_unlock(&osb->osb_lock);
159    }
160
161    return ret;
162}
163
164/* post the our slot info stuff into it's destination bh and write it
165 * out. */
166static void ocfs2_update_disk_slot_extended(struct ocfs2_slot_info *si,
167                        int slot_num,
168                        struct buffer_head **bh)
169{
170    int blkind = slot_num / si->si_slots_per_block;
171    int slotno = slot_num % si->si_slots_per_block;
172    struct ocfs2_slot_map_extended *se;
173
174    BUG_ON(blkind >= si->si_blocks);
175
176    se = (struct ocfs2_slot_map_extended *)si->si_bh[blkind]->b_data;
177    se->se_slots[slotno].es_valid = si->si_slots[slot_num].sl_valid;
178    if (si->si_slots[slot_num].sl_valid)
179        se->se_slots[slotno].es_node_num =
180            cpu_to_le32(si->si_slots[slot_num].sl_node_num);
181    *bh = si->si_bh[blkind];
182}
183
184static void ocfs2_update_disk_slot_old(struct ocfs2_slot_info *si,
185                       int slot_num,
186                       struct buffer_head **bh)
187{
188    int i;
189    struct ocfs2_slot_map *sm;
190
191    sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;
192    for (i = 0; i < si->si_num_slots; i++) {
193        if (si->si_slots[i].sl_valid)
194            sm->sm_slots[i] =
195                cpu_to_le16(si->si_slots[i].sl_node_num);
196        else
197            sm->sm_slots[i] = cpu_to_le16(OCFS2_INVALID_SLOT);
198    }
199    *bh = si->si_bh[0];
200}
201
202static int ocfs2_update_disk_slot(struct ocfs2_super *osb,
203                  struct ocfs2_slot_info *si,
204                  int slot_num)
205{
206    int status;
207    struct buffer_head *bh;
208
209    spin_lock(&osb->osb_lock);
210    if (si->si_extended)
211        ocfs2_update_disk_slot_extended(si, slot_num, &bh);
212    else
213        ocfs2_update_disk_slot_old(si, slot_num, &bh);
214    spin_unlock(&osb->osb_lock);
215
216    status = ocfs2_write_block(osb, bh, INODE_CACHE(si->si_inode));
217    if (status < 0)
218        mlog_errno(status);
219
220    return status;
221}
222
223/*
224 * Calculate how many bytes are needed by the slot map. Returns
225 * an error if the slot map file is too small.
226 */
227static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb,
228                    struct inode *inode,
229                    unsigned long long *bytes)
230{
231    unsigned long long bytes_needed;
232
233    if (ocfs2_uses_extended_slot_map(osb)) {
234        bytes_needed = osb->max_slots *
235            sizeof(struct ocfs2_extended_slot);
236    } else {
237        bytes_needed = osb->max_slots * sizeof(__le16);
238    }
239    if (bytes_needed > i_size_read(inode)) {
240        mlog(ML_ERROR,
241             "Slot map file is too small! (size %llu, needed %llu)\n",
242             i_size_read(inode), bytes_needed);
243        return -ENOSPC;
244    }
245
246    *bytes = bytes_needed;
247    return 0;
248}
249
250/* try to find global node in the slot info. Returns -ENOENT
251 * if nothing is found. */
252static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
253                    unsigned int node_num)
254{
255    int i, ret = -ENOENT;
256
257    for(i = 0; i < si->si_num_slots; i++) {
258        if (si->si_slots[i].sl_valid &&
259            (node_num == si->si_slots[i].sl_node_num)) {
260            ret = i;
261            break;
262        }
263    }
264
265    return ret;
266}
267
268static int __ocfs2_find_empty_slot(struct ocfs2_slot_info *si,
269                   int preferred)
270{
271    int i, ret = -ENOSPC;
272
273    if ((preferred >= 0) && (preferred < si->si_num_slots)) {
274        if (!si->si_slots[preferred].sl_valid) {
275            ret = preferred;
276            goto out;
277        }
278    }
279
280    for(i = 0; i < si->si_num_slots; i++) {
281        if (!si->si_slots[i].sl_valid) {
282            ret = i;
283            break;
284        }
285    }
286out:
287    return ret;
288}
289
290int ocfs2_node_num_to_slot(struct ocfs2_super *osb, unsigned int node_num)
291{
292    int slot;
293    struct ocfs2_slot_info *si = osb->slot_info;
294
295    spin_lock(&osb->osb_lock);
296    slot = __ocfs2_node_num_to_slot(si, node_num);
297    spin_unlock(&osb->osb_lock);
298
299    return slot;
300}
301
302int ocfs2_slot_to_node_num_locked(struct ocfs2_super *osb, int slot_num,
303                  unsigned int *node_num)
304{
305    struct ocfs2_slot_info *si = osb->slot_info;
306
307    assert_spin_locked(&osb->osb_lock);
308
309    BUG_ON(slot_num < 0);
310    BUG_ON(slot_num > osb->max_slots);
311
312    if (!si->si_slots[slot_num].sl_valid)
313        return -ENOENT;
314
315    *node_num = si->si_slots[slot_num].sl_node_num;
316    return 0;
317}
318
319static void __ocfs2_free_slot_info(struct ocfs2_slot_info *si)
320{
321    unsigned int i;
322
323    if (si == NULL)
324        return;
325
326    if (si->si_inode)
327        iput(si->si_inode);
328    if (si->si_bh) {
329        for (i = 0; i < si->si_blocks; i++) {
330            if (si->si_bh[i]) {
331                brelse(si->si_bh[i]);
332                si->si_bh[i] = NULL;
333            }
334        }
335        kfree(si->si_bh);
336    }
337
338    kfree(si);
339}
340
341int ocfs2_clear_slot(struct ocfs2_super *osb, int slot_num)
342{
343    struct ocfs2_slot_info *si = osb->slot_info;
344
345    if (si == NULL)
346        return 0;
347
348    spin_lock(&osb->osb_lock);
349    ocfs2_invalidate_slot(si, slot_num);
350    spin_unlock(&osb->osb_lock);
351
352    return ocfs2_update_disk_slot(osb, osb->slot_info, slot_num);
353}
354
355static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
356                  struct ocfs2_slot_info *si)
357{
358    int status = 0;
359    u64 blkno;
360    unsigned long long blocks, bytes;
361    unsigned int i;
362    struct buffer_head *bh;
363
364    status = ocfs2_slot_map_physical_size(osb, si->si_inode, &bytes);
365    if (status)
366        goto bail;
367
368    blocks = ocfs2_blocks_for_bytes(si->si_inode->i_sb, bytes);
369    BUG_ON(blocks > UINT_MAX);
370    si->si_blocks = blocks;
371    if (!si->si_blocks)
372        goto bail;
373
374    if (si->si_extended)
375        si->si_slots_per_block =
376            (osb->sb->s_blocksize /
377             sizeof(struct ocfs2_extended_slot));
378    else
379        si->si_slots_per_block = osb->sb->s_blocksize / sizeof(__le16);
380
381    /* The size checks above should ensure this */
382    BUG_ON((osb->max_slots / si->si_slots_per_block) > blocks);
383
384    mlog(0, "Slot map needs %u buffers for %llu bytes\n",
385         si->si_blocks, bytes);
386
387    si->si_bh = kzalloc(sizeof(struct buffer_head *) * si->si_blocks,
388                GFP_KERNEL);
389    if (!si->si_bh) {
390        status = -ENOMEM;
391        mlog_errno(status);
392        goto bail;
393    }
394
395    for (i = 0; i < si->si_blocks; i++) {
396        status = ocfs2_extent_map_get_blocks(si->si_inode, i,
397                             &blkno, NULL, NULL);
398        if (status < 0) {
399            mlog_errno(status);
400            goto bail;
401        }
402
403        mlog(0, "Reading slot map block %u at %llu\n", i,
404             (unsigned long long)blkno);
405
406        bh = NULL; /* Acquire a fresh bh */
407        status = ocfs2_read_blocks(INODE_CACHE(si->si_inode), blkno,
408                       1, &bh, OCFS2_BH_IGNORE_CACHE, NULL);
409        if (status < 0) {
410            mlog_errno(status);
411            goto bail;
412        }
413
414        si->si_bh[i] = bh;
415    }
416
417bail:
418    return status;
419}
420
421int ocfs2_init_slot_info(struct ocfs2_super *osb)
422{
423    int status;
424    struct inode *inode = NULL;
425    struct ocfs2_slot_info *si;
426
427    si = kzalloc(sizeof(struct ocfs2_slot_info) +
428             (sizeof(struct ocfs2_slot) * osb->max_slots),
429             GFP_KERNEL);
430    if (!si) {
431        status = -ENOMEM;
432        mlog_errno(status);
433        goto bail;
434    }
435
436    si->si_extended = ocfs2_uses_extended_slot_map(osb);
437    si->si_num_slots = osb->max_slots;
438    si->si_slots = (struct ocfs2_slot *)((char *)si +
439                         sizeof(struct ocfs2_slot_info));
440
441    inode = ocfs2_get_system_file_inode(osb, SLOT_MAP_SYSTEM_INODE,
442                        OCFS2_INVALID_SLOT);
443    if (!inode) {
444        status = -EINVAL;
445        mlog_errno(status);
446        goto bail;
447    }
448
449    si->si_inode = inode;
450    status = ocfs2_map_slot_buffers(osb, si);
451    if (status < 0) {
452        mlog_errno(status);
453        goto bail;
454    }
455
456    osb->slot_info = (struct ocfs2_slot_info *)si;
457bail:
458    if (status < 0 && si)
459        __ocfs2_free_slot_info(si);
460
461    return status;
462}
463
464void ocfs2_free_slot_info(struct ocfs2_super *osb)
465{
466    struct ocfs2_slot_info *si = osb->slot_info;
467
468    osb->slot_info = NULL;
469    __ocfs2_free_slot_info(si);
470}
471
472int ocfs2_find_slot(struct ocfs2_super *osb)
473{
474    int status;
475    int slot;
476    struct ocfs2_slot_info *si;
477
478    mlog_entry_void();
479
480    si = osb->slot_info;
481
482    spin_lock(&osb->osb_lock);
483    ocfs2_update_slot_info(si);
484
485    /* search for ourselves first and take the slot if it already
486     * exists. Perhaps we need to mark this in a variable for our
487     * own journal recovery? Possibly not, though we certainly
488     * need to warn to the user */
489    slot = __ocfs2_node_num_to_slot(si, osb->node_num);
490    if (slot < 0) {
491        /* if no slot yet, then just take 1st available
492         * one. */
493        slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);
494        if (slot < 0) {
495            spin_unlock(&osb->osb_lock);
496            mlog(ML_ERROR, "no free slots available!\n");
497            status = -EINVAL;
498            goto bail;
499        }
500    } else
501        mlog(ML_NOTICE, "slot %d is already allocated to this node!\n",
502             slot);
503
504    ocfs2_set_slot(si, slot, osb->node_num);
505    osb->slot_num = slot;
506    spin_unlock(&osb->osb_lock);
507
508    mlog(0, "taking node slot %d\n", osb->slot_num);
509
510    status = ocfs2_update_disk_slot(osb, si, osb->slot_num);
511    if (status < 0)
512        mlog_errno(status);
513
514bail:
515    mlog_exit(status);
516    return status;
517}
518
519void ocfs2_put_slot(struct ocfs2_super *osb)
520{
521    int status, slot_num;
522    struct ocfs2_slot_info *si = osb->slot_info;
523
524    if (!si)
525        return;
526
527    spin_lock(&osb->osb_lock);
528    ocfs2_update_slot_info(si);
529
530    slot_num = osb->slot_num;
531    ocfs2_invalidate_slot(si, osb->slot_num);
532    osb->slot_num = OCFS2_INVALID_SLOT;
533    spin_unlock(&osb->osb_lock);
534
535    status = ocfs2_update_disk_slot(osb, si, slot_num);
536    if (status < 0) {
537        mlog_errno(status);
538        goto bail;
539    }
540
541bail:
542    ocfs2_free_slot_info(osb);
543}
544
545

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